Helen Doe v. Thomas Horne

FOR PUBLICATION

UNITED STATES COURT OF APPEALS

FOR THE NINTH CIRCUIT

HELEN DOE, parent and next friend No. 23-16026

of Jane Doe; JAMES DOE, parent and

next friend of Jane Doe; KATE ROE, D.C. No. 4:23-cv-

parent and next friend of Megan Roe; 00185-JGZ

ROBERT ROE, parent and next friend

of Megan Roe,

OPINION

Plaintiffs-Appellees,

v.

THOMAS C. HORNE, in his official

capacity as State Superintendent of

Public Instruction; LAURA

TOENJES, in her official capacity as

Superintendent of the Kyrene School

District; KYRENE SCHOOL

DISTRICT; GREGORY SCHOOL;

ARIZONA INTERSCHOLASTIC

ASSOCIATION INCORPORATED,

Defendants,

and

WARREN PETERSEN, Senator,

President of the Arizona State Senate;

2 DOE V. HORNE

BEN TOMA, Representative, Speaker

of the Arizona House of

Representatives,

Intervenor-Defendants-

Appellants.

HELEN DOE, parent and next friend No. 23-16030

of Jane Doe; JAMES DOE, parent and

next friend of Jane Doe; KATE ROE, D.C. No. 4:23-cv-

parent and next friend of Megan Roe; 00185-JGZ

ROBERT ROE, parent and next friend

of Megan Roe,

Plaintiffs-Appellees,

v.

THOMAS C. HORNE, in his official

capacity as State Superintendent of

Public Instruction,

Defendant-Appellant,

and

LAURA TOENJES, in her official

capacity as Superintendent of the

Kyrene School District; KYRENE

SCHOOL DISTRICT; GREGORY

SCHOOL; ARIZONA

INTERSCHOLASTIC

DOE V. HORNE 3

ASSOCIATION INCORPORATED,

Defendants,

WARREN PETERSEN, Senator,

President of the Arizona State Senate;

BEN TOMA, Representative, Speaker

of the Arizona House of

Representatives,

Intervenor-Defendants.

Appeal from the United States District Court

for the District of Arizona

Jennifer G. Zipps, District Judge, Presiding

Argued and Submitted March 14, 2024

San Francisco, California

Filed September 9, 2024

Before: M. Margaret McKeown and Morgan Christen,

Circuit Judges, and David A. Ezra, * District Judge.

Opinion by Judge Christen

*

The Honorable David A. Ezra, United States District Judge for the

District of Hawaii, sitting by designation.

4 DOE V. HORNE

SUMMARY **

Preliminary Injunction/Equal Protection

The panel affirmed the district court’s order

preliminarily enjoining Arizona from barring Plaintiffs Jane

Doe and Megan Roe from playing school sports consistent

with their gender identity.

Plaintiffs are transgender girls who have not gone

through male puberty and who wish to play girls’ sports at

their Arizona schools. In 2022, Arizona enacted the Save

Women’s Sports Act, which prohibits “students of the male

sex,” including transgender women and girls, from

participating in women’s and girls’ sports. The complaint

alleges that the Act’s transgender ban violates, inter alia, the

Equal Protection Clause of the Fourteenth Amendment and

Title IX. Plaintiffs challenge enforcement of the Act solely

as applied to them. The district court concluded that

Plaintiffs were likely to succeed on their equal protection

and Title IX claims, and preliminarily enjoined enforcing the

Act against them.

The panel held that the district court did not clearly err

by finding that, before puberty, there are no significant

differences in athletic performance between boys and girls;

treating small differences as insignificant; and finding that

transgender girls who receive puberty-blocking medication

do not have an athletic advantage over other girls.

**

This summary constitutes no part of the opinion of the court. It has

been prepared by court staff for the convenience of the reader.

DOE V. HORNE 5

The panel affirmed the district court’s holding that

Plaintiffs were likely to succeed on the merits of their equal

protection claim. The district court did not clearly err by

finding that the Act was adopted for the discriminatory

purpose of excluding transgender girls from playing on girls’

sports teams. Accordingly, the district court properly

concluded that the Act is subject to heightened scrutiny.

The panel held that Arizona’s transgender ban

discriminates on its face based on transgender status. To

survive heightened scrutiny, a classification must serve

important governmental objectives and must be substantially

related to the achievement of those objectives. The panel

held that, given the district court’s well-supported factual

findings, the district court properly concluded that

Appellants—the State Superintendent of Public Instruction

and several legislators—are unlikely to establish that the

Act’s sweeping transgender ban is substantially related to the

achievement of the State’s important governmental

objectives in ensuring competitive fairness and equal athletic

opportunity for female student-athletes. The Act’s

transgender ban applies not only to all transgender women

and girls in Arizona, regardless of circulating testosterone

levels or other medically accepted indicia of competitive

advantage, but also to all sports, regardless of the physical

contact involved, the type or level of competition, or the age

or grade of the participants. The district court therefore did

not err by concluding that Plaintiffs are likely to succeed on

the merits of their equal protection claim. Because Plaintiffs

are likely to succeed on the merits of their equal protection

claim, the panel did not reach the issue of whether Plaintiffs

are likely to succeed on the merits of their Title IX claim as

well.

6 DOE V. HORNE

The panel held that the district court did not abuse its

discretion in addressing the remaining preliminary

injunction factors—the likeliness of irreparable harm in the

absence of relief, the balance of the equities, and the public

interest. Accordingly, the panel held that the district court

did not abuse its discretion by granting Plaintiffs’ motion for

a narrow preliminary injunction.

COUNSEL

Justin R. Rassi (argued), Amy C. Zimmerman, and Jyotin R.

Hamid, Debevoise & Plimpton LLP, New York, New York;

Eric M. Fraser and Colin M. Proksel, Osborn Maledon PA,

Phoenix, Arizona; Rachel H. Berg and Amy Whelan,

National Center for Lesbian Rights, San Francisco,

California; for Plaintiffs-Appellees.

Justin D. Smith (argued), Michael E. Talent, and Dean John

Sauer, James Otis Law Group LLC, St. Louis, Missouri;

Maria Syms (argued), Arizona Department of Education,

Phoenix, Arizona; Dennis I. Wilenchik and Karl

Worthington, Wilenchik & Bartness PC, Phoenix, Arizona;

for Intervenor-Defendants-Appellants and Defendants-

Appellants.

Emily Jones and Ryan Lawson, Jones Law Firm PLLC,

Billings, Montana; for Amici Curiae Female Olympic

Rowers Mary I. O'Connor, Carol Brown, Patricia Spratlen

Etem, Valerie McClain, and Jan Palchikoff.

Christopher E. Mills, Spero Law LLC, Mt. Pleasant, South

Carolina; for Amici Curiae Concerned Women for America

and Samaritan's Purse.

DOE V. HORNE 7

William Bock III, Kroger Gardis & Regas LLP,

Indianapolis, Indiana, for Amici Curiae International

Consortium on Female Sport and Independent Council on

Women's Sports.

Jacob P. Warner and Jonathan A. Scruggs, Alliance

Defending Freedom, Scottsdale, Arizona; John J. Bursch,

Alliance Defending Freedom, Washington, D.C.; for

Amicus Curiae Alliance Defending Freedom.

John M. Connolly and James F. Hasson, Consovoy

McCarthy Park PLLC, Arlington, Virginia; for Amicus

Curiae Counsel for Parents Defending Education.

Gene P. Hamilton and James K. Rogers, America First Legal

Foundation, Washington, D.C.; for Amici Curiae Anna Van

Hoek, Lisa Fink, Amber Zenczak, and Arizona Women of

Action.

Gene C. Schaerr and Annika B. Barkdull, Schaerr Jaffe LLP,

Washington, D.C.; Jennifer C. Braceras, Independent

Women's Law Center, Washington, D.C.; for Amicus Curiae

Independent Women's Law Center.

Dylan L. Jacobs, Deputy Solicitor General; Nicholas J.

Bronni, Solicitor General; Tim Griffin, Attorney General;

Office of the Arkansas Attorney General, Little Rock,

Arkansas; Edmund G. LaCour Jr., Solicitor General; Steve

Marshall, Attorney General; Office of the Alabama Attorney

General, Montgomery, Alabama; Treg Taylor, Alaska

Attorney General, Office of the Alaska Attorney General,

Anchorage, Alaska; Chris Carr, Georgia Attorney General,

Office of the Georgia Attorney General, Atlanta, Georgia;

Theodore E. Rokita, Indiana Attorney General, Office of the

Indiana Attorney General, Indianapolis, Indiana; Brenna

Bird, Iowa Attorney General, Office of the Iowa Attorney

8 DOE V. HORNE

General, Des Moines, Iowa; Daniel Cameron, Kentucky

Attorney General, Office of the Kentucky Attorney General,

Frankfort, Kentucky; Jeff Landry, Louisiana Attorney

General, Office of the Louisiana Attorney General, Baton

Rouge, Louisiana; Lynn Fitch, Mississippi Attorney

General, Office of the Mississippi Attorney General,

Jackson, Mississippi; Andrew Bailey, Missouri Attorney

General, Office of the Missouri Attorney General, Kansas

City, Missouri; Austin Knudsen, Montana Attorney General,

Office of the Montana Attorney General, Helena, Montana;

Michael T. Hilgers, Nebraska Attorney General, Office of

the Nebraska Attorney General, Lincoln, Nebraska; Gentner

Drummond, Oklahoma Attorney General, Office of the

Oklahoma Attorney General, Oklahoma City, Oklahoma;

Alan Wilson, South Carolina Attorney General, Office of the

South Carolina Attorney General, Columbia, South

Carolina; Jonathan Skrmetti, Tennessee Attorney General,

Office of the Tennessee Attorney General, Nashville,

Tennessee; Sean D. Reyes, Utah Attorney General, Office of

the Utah Attorney General, Salt Lake City, Utah; Patrick

Morrisey, West Virginia Attorney General, Office of the

West Virginia Attorney General, Charleston, West Virginia;

Bridget Hill, Wyoming Attorney General, Office of the

Wyoming Attorney General, Cheyenne, Wyoming; for

Amici Curiae State of Alabama, State of Arkansas, State of

Alaska, State of Georgia, State of Indiana, State of Iowa,

State of Kentucky, State of Louisiana, State of Mississippi,

State of Missouri, State of Montana, State of Nebraska, State

of Oklahoma, State of South Carolina, State of Tennessee,

State of Utah, State of West Virginia, and State of Wyoming.

Kristine L. Brown, Kristine L. Brown LLC, Denver,

Colorado; for Amici Curiae 88 Female Athletes, Coaches,

Sports Officials, and Parents of Female Athletes.

DOE V. HORNE 9

Omar Gonzalez-Pagan, Lambda Legal Defense & Education

Fund Inc., New York, New York; Sasha Buchert, Lambda

Legal Defense & Education Fund Inc., Washington D.C.;

Kell L. Olson, Lambda Legal Defense & Education Fund

Inc., Los Angeles, California; for Amici Curiae 196 Athletes

in Women’s Sports, The National Women’s Soccer League

Players Association, The Women’s National Basketball

Players Association, Athletes Unlimited, The Women’s

Sports Foundation, and Athlete Ally.

Shireen Barday and Mark C. Davies, Pallas Partner (US)

LLP, New York, New York; Kelly Herbert, Gibson Dunn &

Crutcher LLP, New York, New York; Abbey J. Hudson and

Kate M. Googins, Gibson Dunn & Crutcher LLP, Los

Angeles, California; for Amicus Curiae The Trevor Project,

Inc..

Jordan D. Hershman, Morgan Lewis & Bockius LLP,

Boston, Massachusetts; Stephanie Schuster, Morgan Lewis

& Bockius LLP, Washington, D.C.; for Amici Curiae

GLBTQ Legal Advocates & Defenders, the Human Rights

Campaign Foundation, and the National Center for

Transgender Equality.

Jessica R. Amunson and Illyana A. Green, Jenner & Block

LLP, Washington, D.C.; Matthew D. Cipolla, Jenner &

Block LLP, New York, New York; Chasel Lee, Jenner &

Block LLP, San Francisco, California; Howard S. Suskin

and David M. Kroeger, Jenner & Block LLP, Chicago,

Illinois; for Amici Curiae American Medical Association

and Seven Other Health Care Organizations.

Maia H. Jorgensen and Oren S.A. Kreps, Hogan Lovells

LLP, San Francisco, California; Carolyn A. DeLone and

Katherine I. Culora, Hogan Lovells LLP, Washington, D.C.;

Sarah W. Keller, Hogan Lovells LLP, Tysons, Virginia;

10 DOE V. HORNE

Anaya Marino, Shiwali Patel, Emily Martin, and Auden

Perino, National Women's Law Center, Washington, D.C.;

for Amici Curiae National Women's Law Center and 33

Additional Organizations.

Mark S. Grube, Senior Assistant Solicitor General; Judith N.

Vale, Deputy Solicitor General; Barbara D. Underwood,

Solicitor General; Letitia James, New York Attorney

General; Office of the New York Attorney General, New

York, New York; Lauren K. Chun, Deputy Solicitor

General; Kaliko'onalandi D. Fernandes, Solicitor General;

Anne E. Lopez, Hawaii Attorney General; Office of the

Hawaii Attorney General, Honolulu, Hawaii; Rob Bonta,

California Attorney General, Office of the California

Attorney General, Sacramento, California; Philip J. Weiser,

Attorney General of Colorado, Office of the Colorado

Attorney General, Denver, Colorado; Kathleen Jennings,

Attorney General of Delaware, Office of the Delaware

Attorney General, Wilmington, Delaware; Kwame Raoul,

Illinois Attorney General, Office of the Illinois Attorney

General, Chicago, Illinois; Aaron M. Frey, Maine Attorney

General, Office of the Maine Attorney General, Augusta,

Maine; Anthony G. Brown, Maryland Attorney General,

Office of the Maryland Attorney General, Baltimore,

Maryland; Andrea J. Campbell, Massachusetts Attorney

General, Office of the Massachusetts Attorney General,

Boston, Massachusetts; Dana Nessel, Michigan Attorney

General, Office of the Michigan Attorney General, Lansing,

Michigan; Keith Ellison, Minnesota Attorney General,

Office of the Minnesota Attorney General, St. Paul,

Minnesota; Aaron D. Ford, Nevada Attorney General, Office

of the Nevada Attorney General, Carson City, Nevada;

Matthew J. Platkin, New Jersey Attorney General, Office of

the New Jersey Attorney General, Trenton, New Jersey;

DOE V. HORNE 11

Ellen F. Rosenblum, Oregon Attorney General, Office of the

Oregon Attorney General, Salem, Oregon; Michelle A.

Henry, Pennsylvania Attorney General, Office of the

Pennsylvania Attorney General, Harrisburg, Pennsylvania;

Peter F. Neronha, Rhode Island Attorney General, Office of

the Rhode Island Attorney General, Providence, Rhode

Island; Charity R. Clark, Vermont Attorney General, Office

of the Vermont Attorney General, Montpelier, Vermont;

Robert W. Ferguson, Washington Attorney General, Office

of the Washington Attorney General, Olympia, Washington;

Brian L. Schwalb, District of Columbia Attorney General,

Office of the District of Columbia Attorney General,

Washington, D.C.; for Amici Curiae States of New York,

Hawaii, California, Colorado, Delaware, Illinois, Maine,

Maryland, Massachusetts, Michigan, Minnesota, Nevada,

New Jersey, Oregon, Pennsylvania; Rhode Island, Vermont,

and Washington, and the District of Columbia.

OPINION

CHRISTEN, Circuit Judge:

We address whether the district court abused its

discretion by preliminarily enjoining Arizona from barring

Plaintiffs Jane Doe and Megan Roe from playing school

sports consistent with their gender identity. Given our

limited and deferential review and the district court’s well-

supported factual findings, including its finding that

“[t]ransgender girls who have not undergone male puberty

do not have an athletic advantage over other girls,” Doe v.

Horne, 683 F. Supp. 3d 950, 964 (D. Ariz. 2023), we affirm

the district court’s order granting Plaintiffs’ motion for a

preliminary injunction.

12 DOE V. HORNE

I.

A. 1

Gender identity, “the medical term for a person’s

internal, innate, deeply held sense of their own gender,” is a

“largely biological phenomenon.” Id. at 956. “Research

suggests that differences in prenatal hormonal exposures,

genetic factors, and brain structural differences may all

contribute,” Decl. of Dr. Daniel Shumer, M.D., MPH, ¶ 19,

and “[t]here is a consensus among medical organizations that

gender identity is innate and cannot be changed through

psychological or medical treatments,” Doe, 683 F. Supp. 3d

at 956–57. “When a child is born, a health care provider

identifies the child’s sex based on the child’s observable

anatomy.” Id. at 957. “This identification is known as an

‘assigned sex,’ and in most cases turns out to be consistent

with the person’s gender identity.” Id. For a transgender

person, however, “that initial designation does not match the

person’s gender identity.” Id. A transgender girl is a girl

who was identified as a male at birth but whose gender

identity is female, while a cisgender girl is a girl who was

identified as female at birth and whose gender identity is also

female. Some individuals are nonbinary, meaning they

identify with or express a gender identity that is neither

entirely male nor entirely female. Nonbinary, Merriam-

Webster Online Dictionary, https://www.merriam-

webster.com/dictionary/nonbinary (last visited Aug. 27,

2024).

Transgender persons may suffer from gender dysphoria,

“a serious medical condition characterized by significant and

1

At this stage, we accept this uncontested background information as

true.

DOE V. HORNE 13

disabling distress due to the incongruence between a

person’s gender identity and assigned sex.” Doe, 683 F.

Supp. 3d at 957. “Untreated gender dysphoria can cause

serious harm, including anxiety, depression, eating

disorders, substance abuse, self-harm, and suicide.” Id. at

958. “Attempts to ‘cure’ transgender individuals by forcing

their gender identity into alignment with their birth sex are

harmful and ineffective.” Id. “Those practices have been

denounced as unethical by all major professional

associations of medical and mental health professionals,

such as the American Medical Association, the American

Academy of Pediatrics, the American Psychiatric

Association, and the American Psychological Association,

among others.” Id.

“At the onset of puberty, adolescents with gender

dysphoria may be prescribed puberty-delaying medications

to prevent the distress of developing physical characteristics

that conflict with the[ir] gender identity.” Id. A transgender

girl given puberty blockers “will experience no progression

of physical changes caused by testosterone, including male

muscular development, facial and body hair, an Adam’s

apple, or masculinized facial structures.” Shumer Decl.

¶ 35. “Thereafter, the treating provider may prescribe cross-

sex hormones to induce the puberty associated with the

adolescent’s gender identity.” Id. ¶ 36. “[A] transgender

girl who receives hormone therapy will typically have the

same levels of circulating estrogen and testosterone . . . as

other girls and significantly lower than boys who have begun

pubertal development.” Id.

B.

On March 30, 2022, Arizona enacted Senate Bill 1165,

the Save Women’s Sports Act, codified at Arizona Revised

14 DOE V. HORNE

Statutes § 15-120.02. The Act prohibits “students of the

male sex,” including transgender women and girls, from

participating in women’s and girls’ sports. Id. § 15-

120.02(B). It states:

A. Each interscholastic or intramural athletic

team or sport that is sponsored by a public

school or a private school whose students or

teams compete against a public school shall

be expressly designated as one of the

following based on the biological sex of the

students who participate on the team or in the

sport:

1. “Males,” “men” or “boys.”

2. “Females,” “women” or “girls.”

3. “Coed” or “mixed.”

B. Athletic teams or sports designated for

“females,” “women” or “girls” may not be

open to students of the male sex.

C. This section does not restrict the eligibility

of any student to participate in any

interscholastic or intramural athletic team or

sport designated as being for “males,” “men”

or “boys” or designated as “coed” or

“mixed.”

D. A government entity, any licensing or

accrediting organization or any athletic

association or organization may not entertain

a complaint, open an investigation or take

any other adverse action against a school for

maintaining separate interscholastic or

DOE V. HORNE 15

intramural athletic teams or sports for

students of the female sex.

E. Any student who is deprived of an athletic

opportunity or suffers any direct or indirect

harm as a result of a school knowingly

violating this section has a private cause of

action for injunctive relief, damages and any

other relief available under law against the

school.

F. Any student who is subject to retaliation or

another adverse action by a school or an

athletic association or organization as a result

of reporting a violation of this section to an

employee or representative of the school or

the athletic association or organization, or to

any state or federal agency with oversight of

schools in this state, has a private cause of

action for injunctive relief, damages and any

other relief available under law against the

school or the athletic association or

organization.

G. Any school that suffers any direct or

indirect harm as a result of a violation of this

section has a private cause of action for

injunctive relief, damages and any other

relief available under law against the

government entity, the licensing or

accrediting organization or the athletic

association or organization.

H. All civil actions must be initiated within

two years after the alleged violation of this

section occurred. A person or organization

16 DOE V. HORNE

that prevails on a claim brought pursuant to

this section is entitled to monetary damages,

including damages for any psychological,

emotional or physical harm suffered,

reasonable attorney fees and costs and any

other appropriate relief.

I. For the purposes of this section, “school”

means either:

1. A school that provides instruction in

any combination of kindergarten

programs or grades one through twelve.

2. An institution of higher education.

Id. § 15-120.02. The Act’s ban on transgender female

students playing female sports resides in subsections A and

B. Subsection A requires schools to classify sports and

students by “biological sex,” and Subsection B bans

“students of the male sex” from female-designated sports.

The Act does not define “biological sex,” but the parties

agree that the term is synonymous with sex assigned at birth.

See Doe, 683 F. Supp. 3d at 957. 2 Thus, the Act bans

transgender women and girls from women’s and girls’

sports.

Although the Act purports to ban all “students of the

male sex” from female-designated athletics, including both

2

Although the Act treats sex as binary (male or female), about “two

percent of all babies are born ‘intersex,’ or with ‘a wide range of natural

variations in physical traits—including external genitals, internal sex

organs, chromosomes, and hormones—that do not fit typical binary

notions of male and female bodies.’” Hecox v. Little (Hecox II), 104

F.4th 1061, 1076–77 (9th Cir. 2024), petition for cert. filed (U.S. July

11, 2024) (No. 24-38).

DOE V. HORNE 17

cisgender male students and transgender female students, the

Act in fact has no effect on the ability of cisgender men and

boys to engage in female sports, because they were already

excluded from female sports under the pre-Act status quo.

See, e.g., Clark ex rel. Clark v. Ariz. Interscholastic Ass’n

(Clark I), 695 F.2d 1126, 1127 (9th Cir. 1982) (upholding an

Arizona Interscholastic Association (AIA) policy precluding

cisgender boys from playing on girls’ teams); Clark ex rel.

Clark v. Ariz. Interscholastic Ass’n (Clark II), 886 F.2d

1191, 1192, 1194 (9th Cir. 1989) (same). But the Act has a

profound impact on transgender women and girls. Under

Arizona’s pre-Act status quo, transgender women and girls

in grade school, high school, and college were permitted to

participate in women’s and girls’ sports, albeit under limited

circumstances, consistent with policies established by the

National Collegiate Athletic Association (NCAA), the AIA,

and individual schools. Under current NCAA policy, for

example, transgender women are permitted to compete in

women’s sports when they meet sport-specific standards for

documented testosterone levels. See Transgender Student-

Athlete Participation Policy, NCAA (May 2024),

https://www.ncaa.org/sports/2022/1/27/transgender-

participation-policy.aspx (last visited Aug. 27, 2024). Under

AIA policy, which states that “students should have the

opportunity to participate in [AIA] activities in a manner that

is consistent with their gender identity,” transgender female

students were permitted to play on girls’ teams when a

committee of experts found “that the student’s request is

appropriate and is not motivated by an improper purpose and

there are no adverse health risks to the athlete.” AIA, AIA

Policies & Procedures, art. 41, § 41.9 ( 2022-23). 3 The AIA

3

The AIA is a voluntary association of public and private high schools.

In the dozen or so years before the Act’s passage, the AIA fielded

18 DOE V. HORNE

policy also permitted each school district to set its own rules

governing transgender students’ participation in

intramural—i.e., non-interscholastic—sports. Doe, 683 F.

Supp. 3d at 960.

The Act abrogates these policies by categorically

banning transgender women and girls from women’s and

girls’ sports. As the district court explained, “[u]nlike the

prior case-by-case basis used to approve a transgender girl’s

request to play on a team consistent with her gender identity,

which considered among other things the age and

competitive level relevant to the request, the Act

categorically bans all transgender girls’ participation.” Id. at

962.

The Act’s sweeping transgender ban admits of no

exceptions. The ban applies to all transgender female

students, from kindergarten through graduate school; and for

all sports, including intramural games, regardless of whether

physical contact is involved. Significantly, the ban turns

entirely on a student’s transgender or cisgender status, and

not at all on factors—such as levels of circulating

testosterone—that the district court found bear a genuine

relationship to athletic performance and competitive

advantage. The ban thus applies to many transgender

women and girls who, according to the district court’s

findings, lack an athletic or competitive advantage over

cisgender women and girls, including, for example:

transgender girls such as kindergartners who are too young

to have gone through male puberty; transgender women and

approximately 12 requests from transgender students seeking to play on

teams consistent with their gender identities and approved seven of those

requests. Doe, 683 F. Supp. 3d at 961. The record does not reveal

whether these students were transgender boys or transgender girls. Id.

DOE V. HORNE 19

girls who have received puberty-blocking medication and

hormone therapy and have never gone through male puberty;

and transgender women and girls who have experienced

male puberty but have received sustained hormone therapy

to suppress their circulating testosterone levels.

On its face, the Act treats transgender women and girls

less favorably than all other students. After passage of the

Act, Arizona allows other students—including cisgender

women and girls, cisgender men and boys, and transgender

men and boys—to play on teams corresponding with their

gender identities; only transgender women and girls are

barred from doing so. 4

The Act also singles out women’s and girls’ athletics for

unfavorable treatment. As the district court explained, “[t]he

Act’s creation of a private cause of action against a school

for any student who is deprived of an athletic opportunity or

suffers any harm, whether direct or indirect, related to a

school[’s] failure to preclude participation of a transgender

girl on a girls’ team places an onerous burden on girls’ sports

programs, not faced by boys’ athletic programs.” Id. at 963.

4

That the Act allows transgender men and boys to play on men’s and

boys’ teams does not preclude a finding that the Act discriminates based

on transgender status. As we explained in Hecox II, 104 F.4th at 1079,

“a law is not immune to an equal protection challenge if it discriminates

only against some members of a protected class but not others.” See,

e.g., Rice v. Cayetano, 528 U.S. 495, 516–17 (2000) (“Simply because a

class defined by ancestry does not include all members of the race does

not suffice to make the classification race neutral.”); Nyquist v. Mauclet,

432 U.S. 1, 9 (1977) (“The fact that the statute is not an absolute bar does

not mean that it does not discriminate against the class.”); Mathews v.

Lucas, 427 U.S. 495, 504–05 n.11 (1976) (“That the statutory

classifications challenged here discriminate among illegitimate children

does not mean, of course, that they are not also properly described as

discriminating between legitimate and illegitimate children.”).

20 DOE V. HORNE

“[O]nly girls’ teams fac[e] potential challenges, including

litigation, related to suspected transgender players.” Id.; cf.

Hecox II, 104 F.4th at 1080 (holding that Idaho’s

transgender sports ban discriminated based on sex because it

subjected “only participants in women’s and girls’ sports,

whether cisgender or transgender, to the risk and humiliation

of having their sex ‘disputed’ and then suffering intrusive

medical testing [to have their biological sex verified] as a

prerequisite for participation on school sports teams”).

In legislative findings, the Arizona Legislature suggested

that a categorical transgender ban was justified because,

“[i]n studies of large cohorts of children from six years old,

‘[b]oys typically scored higher than girls on cardiovascular

endurance, muscular strength, muscular endurance, and

speed/agility, but lower on flexibility,’” and “[t]he benefits

that natural testosterone provides to male athletes is not

diminished through the use of testosterone suppression.”

2022 Ariz. Legis. Serv. ch. 106 (S.B. 1165) (West), at § 2,

¶¶ 6, 13 (second alteration in original) (citation omitted).

The legislature also found that “[h]aving separate sex-

specific teams furthers efforts to promote sex equality by

providing opportunities for female athletes to demonstrate

their skill, strength and athletic abilities while also providing

them with opportunities to obtain recognition, accolades,

college scholarships and the numerous other long-term

benefits that flow from success in athletic endeavors.” Id. ¶

14. In a signing statement, Governor Ducey stated that the

Act:

creates a statewide policy to ensure that

biologically female athletes at Arizona public

schools, colleges, and universities have a

level playing field to compete. This bill does

DOE V. HORNE 21

not deny student-athletes the eligibility to

play on teams not designated as “female,”

and it doesn’t impact club sports leagues

offered outside of schools. Every young

Arizona athlete should have the opportunity

to participate in extracurricular activities that

give them a sense of belonging and allow

them to grow and thrive.

This legislation simply ensures that the girls

and young women who have dedicated

themselves to their sport do not miss out on

hard-earned opportunities including their

titles, standings and scholarships due to

unfair competition. This bill strikes the right

balance of respecting all students while still

acknowledging that there are inherent

biological distinctions that merit separate

categories to ensure fairness for all.

2022 Ariz. Legis. Serv. ch. 106 (S.B. 1165) (West)

(Governor’s Approval Message, Mar. 30, 2022). The Act

became effective on September 24, 2022.

C.

In April 2023, Plaintiffs Jane Doe and Megan Roe, by

and through their parents, brought this as-applied challenge

to the Act. Plaintiffs are transgender girls who have not gone

through male puberty and wish to play girls’ sports at their

Arizona schools.

Jane is an 11-year-old transgender girl who attends the

Kyrene Aprende Middle School, a public school located in

Chandler, Arizona, near Phoenix. Doe, 683 F. Supp. 3d at

958. She has lived as a girl in all aspects of her life since she

22 DOE V. HORNE

was five years old and was diagnosed with gender dysphoria

at age seven. Id. She has changed her name through a court

order to a more traditional female name, and she has a female

gender marker on her passport. Id. at 958–59. Jane began

receiving Supprelin, a puberty-blocking medication, in

2023, at age 11. Id. at 959. The district court found that Jane

will not experience any of the physiological changes that

increased testosterone levels would cause in a pubescent

boy. Id.

Sports are important to Jane, and she has played soccer

for many years. Id. Aside from its physical and emotional

health benefits, soccer has helped Jane make new friends and

connect with other girls, and Jane’s teachers, coaches,

friends, and members of her soccer team have all been

supportive of her gender identity. Id. At Aprende, Jane

plays (or is interested in playing) on the girls’ soccer, girls’

basketball, and coed cross-country teams. 5 Id. Aprende,

which participates in the AIA, has no objection to Jane

playing on girls’ teams. Id.

Megan is a 15-year-old transgender girl attending the

Gregory School, a private school in Tucson. Id. Megan has

always known she is a girl, has lived as a girl in all aspects

of her life since she was seven, and was diagnosed with

gender dysphoria at age 10. Id. at 959–60. Through a court

order, Megan has changed her name to a more traditional

female name and her gender to female, and she has a female

gender marker on her passport. Id. at 960. 6 Megan has been

5

Boys and girls train together but compete separately on the coed cross-

country team. Doe, 683 F. Supp. 3d at 959.

6

The court ordered Megan’s name changed; ordered the Office of Vital

Records to amend Megan’s birth record to reflect her new name; and

authorized Megan and her parents to correct her gender designation on

DOE V. HORNE 23

taking puberty blockers since she was 11 and began

receiving hormone therapy at age 12. Id. As a result of these

treatments, the district court found that Megan has not

experienced the physiological changes that increased

testosterone levels would cause in a pubescent boy. Id. On

the contrary, the district court found that she has developed

many of the physiological changes associated with female

puberty. Id.

As with Jane, sports have figured prominently in

Megan’s life. Id. When she was about seven, Megan joined

a swim team, and the coach of the swim team was supportive

of her and her gender identity. Id. At the Gregory School,

Megan is a member of the girls’ volleyball team, although

the Act has barred her from competing in interscholastic

games. Id. at 960, 962. Her teammates, coaches, and school

are all highly supportive of her and have welcomed her

participation on the team. Id. at 960. Like Kyrene Aprende

Middle School, the Gregory School participates in the AIA.

The complaint alleges that the Act’s transgender ban

violates the Equal Protection Clause of the Fourteenth

Amendment to the United States Constitution; Title IX of the

Education Amendments of 1972, 20 U.S.C. § 1681; the

Americans with Disabilities Act of 1990, 42 U.S.C. § 12101

et seq.; and the Rehabilitation Act of 1973, 29 U.S.C. § 794.

The complaint names five defendants: Thomas C. Horne, in

his official capacity as State Superintendent of Public

Instruction; Laura Toenjes, in her official capacity as

Superintendent of the Kyrene School District; the Kyrene

School District; the Gregory School; and the AIA. In

addition, Warren Petersen, President of the Arizona State

her personal, vital, medical, financial, educational, and other public

documents.

24 DOE V. HORNE

Senate, and Ben Toma, Speaker of the Arizona House of

Representatives (the “Legislators”), have intervened as

defendants.

Plaintiffs neither challenge the existence of separate

teams for girls and boys nor challenge the Act facially.

Rather, they challenge enforcement of the Act solely as

applied to them. They seek injunctive and declaratory relief

in the form of an order allowing them to participate in their

chosen sports.

D.

Contemporaneous with the filing of the complaint,

Plaintiffs moved to preliminarily enjoin the defendants from

enforcing the Act as applied to them. Plaintiffs sought relief

on the grounds that they were likely to succeed on their equal

protection and Title IX claims. In July 2023, after

considering the parties’ briefs, evidentiary submissions from

numerous experts, and argument presented at a hearing, the

district court granted the motion. Doe, 683 F. Supp. 3d at

955–77. The preliminary injunction order includes a number

of factual findings relevant to this appeal. The district court

found that “[t]he Act was adopted for the purpose of

excluding transgender girls from playing on girls’ sports

teams.” Id. at 963. The district court also found that,

“[b]efore puberty, there are no significant differences in

athletic performance between boys and girls.” Id. at 968.

The court acknowledged studies showing that prepubertal

boys outperform prepubertal girls on school physical fitness

tests, but the court found “no basis . . . to attribute those

small differences to physiology or anatomy instead of to

other factors such as greater societal encouragement of

athleticism in boys, greater opportunities for boys to play

DOE V. HORNE 25

sports, or differences in the preferences of the boys and girls

surveyed.” Id. at 966.

The district court also found that “[t]he biological driver

of average group differences in athletic performance

between adolescent boys and girls is the difference in their

respective levels of testosterone, which only begin to diverge

significantly after the onset of puberty,” and that puberty

typically begins at around age 12. Id. at 968. More

specifically, the court cited “the scientific consensus that the

biological cause of average differences in athletic

performance between men and women is . . . the presence of

circulating levels of testosterone beginning with male

puberty . . . between the ages of about 12 and 18.” Id. at

964–65. Accordingly, the court found that transgender girls

such as Plaintiffs, who begin puberty-blocking medication

and hormone therapy at an early age, “do not have an athletic

advantage over other girls.” Id. at 964. The court found that

“[t]ransgender girls who receive puberty-blocking

medication do not have an athletic advantage over other girls

because they do not undergo male puberty and do not

experience the physiological changes caused by the

increased production of testosterone associated with male

puberty.” Id. at 968. It also found that “[t]ransgender girls

who receive hormone therapy after receiving puberty-

blocking medication will develop the skeletal structure, fat

distribution, and muscle and breast development typical of

other girls” and “will typically have the same levels of

circulating estrogen and testosterone as other girls.” Id.

Finally, the district court found that “transgender girls who

have not yet undergone male puberty or who have received

puberty-blocking medication at the onset of puberty do not

present any unique safety risk to other girls.” Id.

26 DOE V. HORNE

On the strength of these findings, the district court

concluded that Plaintiffs were likely to succeed on their

equal protection challenge to the transgender ban. As a

threshold matter, the court concluded that heightened

scrutiny applies because the Act discriminates against

transgender girls both purposely and on its face. Id. at 971–

72. Applying heightened scrutiny, the court concluded that

Horne and the Legislators—the only defendants actively

defending the ban—failed to “establish[] that categorically

banning all transgender girls from playing girls’ sports is

substantially related to an important government interest.”

Id. at 973. The court concluded that their “argument that the

Act is necessary to protect girls’ sports by barring

transgender girls, who purportedly have an unfair athletic

advantage over other girls and/or pose a safety risk to other

girls, is based on overbroad generalizations and stereotypes

that erroneously equate transgender status with athletic

ability.” Id. at 973–74.

The district court also determined that Plaintiffs were

likely to succeed on their Title IX claim, that Plaintiffs

would suffer irreparable harm if relief were not granted, and

that the public interest and the balance of the equities favored

relief. Id. at 974–76. Accordingly, the court granted

Plaintiffs motion and preliminarily enjoined Horne from

enforcing the Act against Plaintiffs. Id. at 977. Horne and

the Legislators (collectively, “Appellants”) filed separate

timely appeals that we subsequently consolidated.

II.

“The ‘purpose of a preliminary injunction is to preserve

the status quo ante litem pending a determination of the

action on the merits.’” Boardman v. Pac. Seafood Grp., 822

F.3d 1011, 1024 (9th Cir. 2016) (quoting Sierra Forest

DOE V. HORNE 27

Legacy v. Rey, 577 F.3d 1015, 1023 (9th Cir. 2009)). “A

plaintiff seeking a preliminary injunction must establish

[1] that he is likely to succeed on the merits, [2] that he is

likely to suffer irreparable harm in the absence of

preliminary relief, [3] that the balance of equities tips in his

favor, and [4] that an injunction is in the public interest.”

Johnson v. Couturier, 572 F.3d 1067, 1078 (9th Cir. 2009)

(brackets in original) (quoting Winter v. Nat. Res. Def.

Council, Inc., 555 U.S. 7, 20 (2008)). The third and fourth

factors, harm to the opposing party and weighing the public

interest, “merge when the Government is the opposing

party.” Nken v. Holder, 556 U.S. 418, 435 (2009). With

respect to the fourth factor, “it is always in the public interest

to prevent the violation of a party’s constitutional rights,”

Melendres v. Arpaio, 695 F.3d 990, 1002 (9th Cir. 2012)

(quoting Sammartano v. First Jud. Dist. Ct., 303 F.3d 959,

974 (9th Cir. 2002), abrogated on other grounds by Winter,

555 U.S. 7), because “all citizens have a stake in upholding

the Constitution,” Preminger v. Principi, 422 F.3d 815, 826

(9th Cir. 2005). But “[a] preliminary injunction is an

extraordinary remedy never awarded as of right.” Winter,

555 U.S. at 24.

“We review the grant or denial of a preliminary

injunction for abuse of discretion.” Johnson, 572 F.3d at

1078 (quoting Am. Trucking Ass’ns v. City of Los Angeles,

559 F.3d 1046, 1052 (9th Cir. 2009)). “This review is

‘limited and deferential,’ and it does not extend to the

underlying merits of the case.” Id. (quoting Am. Trucking

Ass’ns, 559 F.3d at 1052). “A district court ‘necessarily

abuses its discretion when it bases its decision on an

erroneous legal standard or on clearly erroneous findings of

fact.’” Id. at 1078–79 (quoting Am. Trucking Ass’ns, 559

F.3d at 1052). “But ‘[a]s long as the district court got the

28 DOE V. HORNE

law right, it will not be reversed simply because the appellate

court would have arrived at a different result if it had applied

the law to the facts of the case.’” Id. at 1079 (alteration in

original) (quoting Am. Trucking Ass’ns, 559 F.3d at 1052);

accord Wildwest Inst. v. Bull, 472 F.3d 587, 590 (9th Cir.

2006). “A district court’s factual finding is clearly erroneous

‘if it is illogical, implausible, or without support in

inferences that may be drawn from the facts in the record.’”

Porretti v. Dzurenda, 11 F.4th 1037, 1047 (9th Cir. 2021)

(quoting Arc of California v. Douglas, 757 F.3d 975, 984

(9th Cir. 2014)). “Although we review [legislative]

factfinding under a deferential standard, . . . [t]he Court

retains an independent constitutional duty to review factual

findings where constitutional rights are at stake.” Gonzales

v. Carhart, 550 U.S. 124, 165 (2007) (citing Crowell v.

Benson, 285 U.S. 22, 60 (1932)). We review a district

court’s finding of discriminatory purpose for clear error. See

Alexander v. S.C. State Conf. of the NAACP, 144 S. Ct. 1221,

1240–41 (2024); Hernandez v. New York, 500 U.S. 352,

364–65 (1991) (collecting cases); Hunter v. Underwood, 471

U.S. 222, 229 (1985).

III.

We begin with Appellants’ contention that the district

court’s factual findings regarding the expert medical

evidence are clearly erroneous. Specifically, Appellants

argue that the district court clearly erred by: (1) finding that,

before puberty, there are no significant differences in athletic

performance between boys and girls; (2) treating small

differences as insignificant; and (3) finding that transgender

girls who receive puberty-blocking medication do not have

an athletic advantage over other girls. We sustain these

findings because they are not “illogical, implausible, or

without support in inferences that may be drawn from the

DOE V. HORNE 29

record.” United States v. Hinkson, 585 F.3d 1247, 1263 (9th

Cir. 2009) (en banc). Appellants have not shown that the

district court clearly erred.

A.

The district court’s finding that, “[b]efore puberty, there

are no significant differences in athletic performance

between boys and girls,” Doe, 683 F. Supp. 3d at 968, is not

clearly erroneous. Dr. Daniel Shumer is a Pediatric

Endocrinologist and Medical Director of the Comprehensive

Gender Services Program at Michigan Medicine, University

of Michigan; the Clinical Director of Child and Adolescent

Gender Services at C.S. Mott Children’s Hospital; and an

Assistant Professor of Medicine at the University of

Michigan, where the major focus of his clinical and research

work pertains to transgender adolescents. Shumer Decl. ¶ 3.

He has personally evaluated and treated over 400 patients for

gender dysphoria and has knowledge of the scientific

literature concerning the issues raised in this litigation. Id.

¶¶ 7, 14. Dr. Shumer stated that, “[b]efore puberty, there are

no significant differences in athletic performance between

boys and girls.” Id. ¶ 38. He acknowledged that “some

studies have found small differences between the

performance of boys and girls with respect to some discrete

activities,” but he noted that “these studies did not control

for other factors, particularly age, location, or

socioeconomic factors.” Rebuttal Decl. of Daniel Shumer,

M.D., ¶ 10. He further explained, “When research has

controlled for those factors by using representative data,

researchers have found . . . ‘no statistical difference in the

capabilities of girls and boys until high-school age

(commonly age 12).’” Id. ¶ 11. According to Dr. Shumer,

“[t]here is no reliable basis . . . to attribute those small

differences to physiology or anatomy instead of other

30 DOE V. HORNE

factors, such as greater societal encouragement of

athleticism in boys, greater opportunities for boys to play

sports, or different preferences of the boys and girls

surveyed.” Id. ¶ 13; see also Second Rebuttal Decl. of

Daniel Shumer, M.D., ¶¶ 16–24.

Appellants point to a handful of studies suggesting that

prepubertal boys may be taller, weigh more, have more

muscle mass, have less body fat, or have greater shoulder

internal rotator strength than prepubertal girls. These

studies, however, neither attributed these differences to

biological rather than sociological factors nor concluded that

these differences translated into competitive athletic

advantages. Moreover, the results of these studies are

disputed. Dr. Shumer, for example, testified that studies

have found “no statistical difference in the [muscle strength]

of girls and boys until high-school age” and that height

differences between boys and girls “disappear around age 6

to 8 years of age, and do not begin diverging again until

puberty,” when girls acquire an advantage. Shumer 2d

Rebuttal Decl. ¶¶ 13, 18. On appeal, Appellants cite the

findings of these studies selectively. For example, although

a 2017 study found that prepubertal boys had greater

shoulder internal rotator strength than prepubertal girls, the

study also found “no significant . . . differences between

strength measures of boys or girls aged 3–9 years” with

respect to the 12 other muscle groups studied. Marnee J.

McKay et al., Normative Reference Values for Strength and

Flexibility of 1,000 Children and Adults, 88 Neurology 36,

38 (2017). And Appellants’ reliance on a 2023 study, Mira

A. Atkinson et al., Sex Differences in Track and Field Elite

Youth 10–11 (2023) (preprint),

https://sportrxiv.org/index.php/server/preprint/view/324/65

4 (last visited Aug. 27, 2024), is misplaced because it does

DOE V. HORNE 31

not appear that Appellants presented this evidence to the

district court. “Our review of the district court’s findings,

pursuant to its action on a motion for preliminary judgment

is . . . restricted to the limited record available to the district

court when it granted or denied the motion.” Sports Form,

Inc. v. United Press Int’l, Inc., 686 F.2d 750, 753 (9th Cir.

1982).

On the record before it, the district court did not clearly

err by finding that there are no significant differences in

athletic performance between prepubescent boys and girls.

We recognize that Appellants’ experts—including Dr.

Emma Hilton, Ph.D., a postdoctoral researcher in

developmental biology at the University of Manchester, UK,

and Dr. Gregory A. Brown, Ph.D., FACSM, a Professor of

Exercise Science in the Department of Kinesiology and

Sport Sciences at the University of Nebraska Kearney—

disagree with these findings, but our review of a district

court’s factual findings is limited and deferential, especially

at this stage of the proceedings. Because the challenged

findings are firmly grounded in evidence in the record, they

are not clearly erroneous.

B.

Appellants contend the district court clearly erred by

treating small differences between prepubertal boys and girls

as insignificant. They note that small differences can “have

an enormous influence in competitive sports, where

outcomes are routinely decided by tiny margins.” Opening

Br. at 56. Appellants overlook the court’s finding that the

small differences that have been identified by some studies

have not been shown to be attributable to biological rather

than sociological factors. Doe, 683 F. Supp. 3d at 966. The

court found that “any prepubertal differences between boys

32 DOE V. HORNE

and girls in various athletic measurements are minimal or

nonexistent” and that there is “no basis . . . to attribute” the

small differences observed in school-based fitness testing of

prepubertal boys and girls “to physiology or anatomy instead

of to other factors such as greater societal encouragement of

athleticism in boys, greater opportunities for boys to play

sports, or differences in the preferences of the boys and girls

surveyed.” Id. at 966–67. These findings are supported by

the record and are not clearly erroneous. 7

C.

Appellants also take issue with the district court’s

finding that “[t]ransgender girls who receive puberty-

blocking medication do not have an athletic advantage over

other girls because they do not undergo male puberty and do

not experience the physiological changes caused by the

increased production of testosterone associated with male

puberty.” Id. at 968. Appellants point to what they describe

as “abundant evidence showing that preventing male puberty

does not eliminate the advantages that [transgender females]

have over [cisgender] females.” Opening Br. at 52.

The district court’s finding is grounded in the record

evidence. Dr. Shumer testified that transgender girls

receiving treatment consistent with current standards of care

begin puberty blockers “at the first onset of puberty, . . . long

before the development of increased muscle mass and

strength associated with the later stages of male puberty,”

7

Because Appellants failed to show that there are differences in athletic

performance between prepubertal boys and girls that are attributable to

biology, the district court had no occasion to address whether slight

differences of that nature would justify a categorical ban on transgender

women and girls playing women’s and girls’ sports. We likewise

express no opinion on that question.

DOE V. HORNE 33

and “receive hormone therapy to allow them to go through

puberty consistent with their female gender identity.”

Shumer 2d Rebuttal Decl. ¶¶ 26–27. Consequently, Dr.

Shumer testified that these transgender girls “will develop

many of the same physiological and anatomical

characteristics of non-transgender girls, including bone size,

skeletal structure, and distinctive aspects of the female pelvis

geometry that cut against athletic performance. . . . Because

such girls do not undergo male puberty, they do not gain the

increased muscle mass or strength that accounts for why

post-pubertal boys as a group have an advantage over post-

pubertal girls as a group.” Id. ¶¶ 27–28. Dr. Shumer

testified, there is “no evidence that transgender girls on

puberty suppression medication or hormone therapy have an

athletic advantage over other girls,” there are “no studies that

have documented any such advantage,” and there is “no

medical reason to posit that any such advantage would

exist.” Id. ¶ 36; see also Shumer Rebuttal Decl. ¶¶ 14–27.

Dr. Shumer also cited “the scientific consensus that the

biological cause of average differences in athletic

performance between men and women is the rise of

circulating levels of testosterone beginning in endogenous

male puberty.” Shumer Rebuttal Decl. ¶ 8. Dr. Shumer

further testified that “a transgender girl who receives

hormone therapy will typically have the same levels of

circulating estrogen and testosterone levels as other girls.”

Shumer Decl. ¶ 36.

Relying on several studies, Appellants argue that

transgender females who receive puberty blockers have

advantages over cisgender females in lean body mass, grip

strength, and height. But Appellants overlook that in these

studies, male puberty was only partially blocked. In the lean

body mass study, for example, the transgender women

34 DOE V. HORNE

participants “had much more testosterone exposure than

transgender girls treated with modern protocols” because

they started puberty blockers at an average age of 14.5 years.

Shumer 2d Rebuttal Decl. ¶ 33; see Maartje Klaver et al.,

Early Hormonal Treatment Affects Body Composition and

Body Shape in Young Transgender Adolescents, 15 J. Sexual

Med. 251 (2018). Plaintiffs, by contrast, began receiving

puberty blockers at age 11. Similarly, the height study upon

which Appellants rely considered “transgender girls who

had received puberty blockers from around 13 years of age”

and “cross-sex hormones at 16 years of age”—far later than

Plaintiffs and others following current protocols. Statement

of Emma Hilton, Ph.D., ¶ 11.2; see Lidewij Sophia Boogers

et al., Transgender Girls Grow Tall: Adult Height Is

Unaffected by GnRH Analogue and Estradiol Treatment,

107 J. Clinical Endocrinology & Metabolism 3805 (2022).

The medications in the grip strength study cited by

Appellants “did not fully block puberty” and were “less

effective” than the puberty blockers used in the United

States. Shumer 2d Rebuttal Decl. ¶ 34; see Lloyd J.W. Tack

et al., Proandrogenic and Antiandrogenic Progestins in

Transgender Youth: Differential Effects on Body

Composition and Bone Metabolism, 103 J. Clinical

Endocrinology & Metabolism 2147 (2018). Given the

limited relevance of these studies, the district court did not

clearly err.

IV.

The district court concluded that Plaintiffs were likely to

succeed on their equal protection and Title IX claims. We

discuss these claims in turn, beginning with equal protection.

DOE V. HORNE 35

A.

1.

In Karnoski v. Trump, 926 F.3d 1180, 1200–01 (9th Cir.

2019), and Hecox II, 104 F.4th at 1079, we held that

heightened scrutiny applies to laws that discriminate based

on transgender status. Thus, if the Act discriminates based

on transgender status, either purposefully or on its face,

heightened scrutiny applies. 8

a.

A discriminatory purpose is shown when “the

decisionmaker, in this case a state legislature, selected or

reaffirmed a particular course of action at least in part

‘because of,’ not merely ‘in spite of,’ its adverse effects upon

an identifiable group.” Pers. Adm’r v. Feeney, 442 U.S. 256,

279 (1979). “Determining whether invidious discriminatory

purpose was a motivating factor demands a sensitive inquiry

into such circumstantial and direct evidence of intent as may

be available.” Village of Arlington Heights v. Metro. Hous.

Dev. Corp., 429 U.S. 252, 266 (1977). “The ‘important

starting point’ for assessing discriminatory intent under

Arlington Heights is ‘the impact of the official action

8

We recognize that the Act also classifies based on sex, but Plaintiffs do

not challenge the State’s decision to require that schools maintain

separate teams for girls and boys, so we do not address it. See Doe, 683

F. Supp. 3d at 967 (“The Plaintiffs do not challenge the existence of

separate teams for girls and boys.”); cf. B.P.J. ex rel. Jackson v. W. Va.

State Bd. of Educ., 98 F.4th 542, 557 (4th Cir. 2024) (“Because [the

challenged law’s] requirement that all teams be designated male, female,

or co-ed . . . is conceded to be valid and is necessary to the relief

[plaintiff] seeks (being allowed to participate in girls cross country and

track teams) we need go no further in determining whether the State can

justify it.”), petitions for cert. filed (July 16, 2024) (Nos. 24-43, 24-44).

36 DOE V. HORNE

whether it ‘bears more heavily on one race than another.’”

Reno v. Bossier Par. Sch. Bd., 520 U.S. 471, 489 (1997)

(quoting Village of Arlington Heights, 429 U.S. at 266).

“Other considerations relevant to the purpose inquiry

include, among other things, ‘the historical background of

the [jurisdiction’s] decision’; ‘[t]he specific sequence of

events leading up to the challenged decision’; ‘[d]epartures

from the normal procedural sequence’; and ‘[t]he legislative

or administrative history, especially . . . [any] contemporary

statements by members of the decisionmaking body.’” Id.

(alterations in original) (quoting Village of Arlington

Heights, 429 U.S. at 268). Although we start with a

presumption that a legislature acted in good faith, a plaintiff

need demonstrate only that discrimination against a

protected class “was a substantial or motivating factor in

enacting the challenged provision,” not the sole or

predominant factor. United States v. Carrillo-Lopez, 68

F.4th 1133, 1139–40 (9th Cir. 2023). Here, the district court

found that “[t]he Act was adopted for the purpose of

excluding transgender girls from playing on girls’ sports

teams.” Doe, 683 F. Supp. 3d at 963. This finding is not

clearly erroneous.

First, Appellants’ contention that the legislature adopted

the Act to ensure competitive fairness and equal athletic

opportunities for cisgender female athletes cannot be

squared with the fact that the Act bars students from female

athletics based entirely on transgender status and not at all

based on factors the district court found bear a genuine

connection to athletic performance and competitive

advantage, such as circulating testosterone. The district

court concluded that “[t]he Arizona legislature intentionally

created a classification, specifically ‘biological girls,’ that

necessarily excludes transgender girls,” id. at 971, and that

DOE V. HORNE 37

“[t]he categorical preclusion of transgender women,

especially girls who have not experienced male puberty,

appears unrelated to the interests the Act purportedly

advances,” id. at 967.

Second, the Supreme Court has long recognized that a

policy’s discriminatory impact may support a finding of

discriminatory purpose. See Crawford v. Bd. of Educ., 458

U.S. 527, 544 (1982) (“In determining whether . . . a

[discriminatory] purpose was the motivating factor, the

racially disproportionate effect of official action provides

‘an important starting point.’” (quoting Feeney, 442 U.S. at

274 (in turn quoting Village of Arlington Heights, 429 U.S.

at 266))). Here, the Act’s transgender ban affects only

transgender female students. To be sure, the statutory

language bans all “students of the male sex” from female

sports. Ariz. Rev. Stat. § 15-120.02(B). But Appellants

have not shown that the Act had any real-world impact on

cisgender male students, who have long been excluded from

female sports in Arizona and elsewhere. See Clark I, 695

F.2d at 1127; Clark II, 886 F.2d at 1192. 9

The Act’s burdens instead fall exclusively on transgender

women and girls. Under the pre-Act status quo, transgender

women and girls were permitted to participate in women’s

and girls’ sports consistent with AIA, NCAA, and

9

Appellants contend the Act affects cisgender males because there was

no state law explicitly barring cisgender males from female sports before

the Act’s adoption and because AIA and NCAA policies excluding

cisgender males from female sports applied only to member schools, not

to other schools, and only to colleges and high schools, not to

kindergarten through eighth grade. This argument fails because the Act

merely codifies preexisting rules barring cisgender males from

participating on girls’ sports teams, and it had no practical effect on

cisgender males.

38 DOE V. HORNE

individual-school policies. The Act functions solely to

abrogate those policies, and thus burdens only transgender

female students. Cf. Hecox II, 104 F.4th at 1077 (“[T]he

Act’s discriminatory purpose is . . . evidenced by the Act’s

prohibition of ‘biological males’ from female-designated

teams because that prohibition affects one group of athletes

only—transgender women. . . . The Act’s only contribution

to Idaho’s student-athletic landscape is to entirely exclude

transgender women and girls from participating on female

sports teams.”); B.P.J., 98 F.4th at 556 (applying heightened

scrutiny where the challenged legislation’s “only effect” was

“to exclude transgender girls . . . from participation on girls

sports teams”). 10

In sum, the district court did not clearly err by finding a

discriminatory purpose. Accordingly, the district court

properly concluded that the Act is subject to heightened

scrutiny on this basis.

b.

Turning to facial discrimination, Appellants contend the

Act “is ‘facially’ neutral with respect to gender identity”

10

The district court also found evidence of discriminatory purpose in the

legislative history, noting that Senator Vince Leach explained his vote

for the bill by stating, “if we allow transgenders to take over female

sports, you will not have females participating,” and that Senator

Petersen, Chairman of the Senate Committee on Judiciary, questioned

whether critics of the bill would “be opposed to having just a trans

league, so that they can all compete in their own league.” Doe, 683 F.

Supp. 3d at 963. Speakers at the legislative hearing on the bill also

referred to transgender women and girls as “males” and “men.” See

Hearing on Senate Bill 1165, Arizona State Senate, Committee on the

Judiciary, Jan. 20, 2022, available at

https://www.azleg.gov/videoplayer/?eventID=2022011057&startStrea

mAt=508 (last visited Aug. 27, 2024).

DOE V. HORNE 39

because it “describes who may play on what sports teams

‘without referring to’ gender identity.” Opening Br. at 32.

They rely on Martin v. International Olympic Committee,

740 F.2d 670, 678 (9th Cir. 1984), which held that an IOC

rule was gender neutral because it “describe[d] the

procedures for determining events to be included in the

Olympic Games without referring to the competitors’ sex.”

Under circuit precedent, however, the Act discriminates on

its face based on transgender status.

In Latta v. Otter, 771 F.3d 456 (9th Cir. 2014), we held

that state laws defining marriage as between a man and a

woman, but making no mention of sexual orientation,

discriminated on their face based on sexual orientation. Id.

at 464 n.2, 467–68. Although the challenged laws prohibited

all same-sex couples from marrying, whether gay or straight,

the laws facially discriminated based on sexual orientation

because only gay couples were barred from marrying

consistent with their sexual orientation. This precedent

applies here. The Act bars all “students of the male sex”

from playing on female teams, but only transgender female

students are prohibited from playing on teams consistent

with their gender identity, and this distinction is plain from

the face of the statute. Thus, under Latta, the Act

discriminates on its face based on transgender status.

In Hecox II, moreover, we held that an Idaho transgender

ban similar to the Arizona law challenged here discriminated

on its face based on transgender status. We reasoned that

“the Act’s use of ‘biological sex’ functions as a form of

‘[p]roxy discrimination’” because the Act’s “definition of

‘biological sex’” was “carefully drawn to target transgender

women and girls, even if it does not use the word

‘transgender’ in the definition.” Hecox II, 104 F.4th at 1078

(quoting Pac. Shores Props., LLC v. City of Newport Beach,

40 DOE V. HORNE

730 F.3d 1142, 1160 n.23 (9th Cir. 2013)). 11 We reach the

same conclusion here; under Hecox II, Arizona’s

transgender ban discriminates on its face based on

transgender status.

This conclusion is consistent not only with common

sense—there is simply no denying that a transgender sports

ban discriminates based on transgender status—but also with

the decisions of other courts, which have held that

transgender sports bans like the one challenged here

discriminate on their face against transgender women and

girls. See id. (“In addition to having a discriminatory

purpose and effect, the Act is also facially discriminatory

against transgender female athletes.”); B.P.J., 98 F.4th at

555–56 (“If B.P.J. were a cisgender girl, she could play on

her school’s girls teams. Because she is a transgender girl,

she may not. The Act declares a person’s sex is defined only

by their ‘reproductive biology and genetics at birth.’ The

undisputed purpose—and the only effect—of that definition

is to exclude transgender girls from the definition of ‘female’

11

In Pacific Shores Properties, we explained:

Proxy discrimination is a form of facial

discrimination. It arises when the defendant enacts a

law or policy that treats individuals differently on the

basis of seemingly neutral criteria that are so closely

associated with the disfavored group that

discrimination on the basis of such criteria is,

constructively, facial discrimination against the

disfavored group. For example, discriminating against

individuals with gray hair is a proxy for age

discrimination because “the ‘fit’ between age and gray

hair is sufficiently close.”

730 F.3d at 1160 n.23 (quoting McWright v. Alexander, 982 F.2d 222,

228 (7th Cir. 1992)).

DOE V. HORNE 41

and thus to exclude them from participation on girls

sports teams. That is a facial classification based on gender

identity.”); Hecox v. Little (Hecox I), 479 F. Supp. 3d 930,

975 (D. Idaho 2020) (“[T]he Act on its face discriminates

between cisgender athletes, who may compete on athletic

teams consistent with their gender identity, and transgender

women athletes, who may not compete on athletic teams

consistent with their gender identity.”).

c.

Citing Katzenbach v. Morgan, 384 U.S. 641 (1966), and

Jana-Rock Construction, Inc. v. New York State Department

of Economic Development, 438 F.3d 195 (2d Cir. 2006),

Appellants argue that rational basis review applies to the

Plaintiffs’ equal protection claim because Plaintiffs assert an

underinclusiveness challenge to a remedial statute.

In Morgan, 384 U.S. at 656, the Supreme Court

considered a Fifth Amendment equal protection challenge to

a Voting Rights Act provision prohibiting states from

denying the vote to some non-English speakers (those

educated in schools in Puerto Rico or other U.S. territories)

but not to other non-English speakers (those educated

beyond U.S. territories). Although classifications based on

national origin ordinarily trigger strict scrutiny, the Court

held that rational basis review applied because “the

distinction challenged by appellees is presented only as a

limitation on a reform measure aimed at eliminating an

existing barrier to the exercise of the franchise.” Id. at 657.

The Court noted that a “statute is not invalid under the

Constitution because it might have gone farther than it did,”

that a legislature need not “strike at all evils at the same

time,” and that “reform may take one step at a time,

addressing itself to the phase of the problem which seems

42 DOE V. HORNE

most acute to the legislative mind.” Id. (first quoting

Roschen v. Ward, 279 U.S. 337, 339 (1929), then quoting

Semler v. Oregon State Bd. of Dental Examiners, 294 U.S.

608, 610 (1935), and then quoting Williamson v. Lee Optical

of Okla. Inc., 348 U.S. 483, 489 (1955)). In Jana-Rock, the

Second Circuit considered a Fourteenth Amendment equal

protection challenge to a New York affirmative action

program providing benefits to some Hispanics (those from

Latin America) but not to other Hispanics (those from Spain

and Portugal). Although racial classifications ordinarily

prompt strict scrutiny, the Second Circuit applied rational

basis review because “once the government has shown that

its decision to resort to explicit racial classifications survives

strict scrutiny by being narrowly tailored to achieve a

compelling interest, its program is no longer presumptively

suspect.” 438 F.3d at 200. The court declined “to apply

automatically strict scrutiny a second time in determining

whether an otherwise valid affirmative action program is

underinclusive for having excluded a particular plaintiff.”

Id.; see also id. at 206–11.

Relying on Morgan and Jana-Rock, Appellants argue

that rational basis review applies here. They argue that the

Act “is a remedial statute” because “[t]he Arizona legislature

passed the law to provide girls and women a benefit—

participation on their own sports teams—for the purpose of

promoting opportunities for female athletes, ensuring the

safety of female athletes, and remedying past

discrimination.” Opening Br. at 18. Further, they argue that

Plaintiffs’ equal protection claim should be understood as an

underinclusiveness challenge because, rather than

challenging Arizona’s adoption of “sex-segregated sports

teams,” in their view Plaintiffs’ claim is “that the definition

of ‘females,’ ‘women,’ and ‘girls’ in the [Act] is

DOE V. HORNE 43

underinclusive—that the definition should be expanded to

include not just biological females, but also at least some

biological males who identify as females, i.e., transgender

athletes like themselves.” Id. at 2.

Appellants’ argument rests on the flawed premise that

the Act qualifies as remedial legislation. The district court

found that “[t]he Act was adopted for the purpose of

excluding transgender girls from playing on girls’ sports

teams,” Doe, 683 F. Supp. 3d at 963, and, as discussed

earlier, that finding is not clearly erroneous. Thus, the Act

is not remedial, and Morgan and Jana-Rock do not control.

Furthermore, even in the context of an underinclusiveness

challenge to a remedial statute, heightened scrutiny applies

where, as here, the plaintiff “demonstrate[s] that his or her

exclusion was motivated by a discriminatory purpose.”

Jana-Rock, 428 F.3d at 200. Thus, even under Jana-Rock,

heightened scrutiny applies here.

2.

To withstand heightened scrutiny, a classification “must

serve important governmental objectives and must be

substantially related to achievement of those objectives.”

Clark I, 695 F.2d at 1129 (quoting Craig v. Boren, 429 U.S.

190, 197 (1976)). The State bears the burden of

demonstrating an “exceedingly persuasive justification” for

the classification, United States v. Virginia, 518 U.S. 515,

531 (1996), and “[t]he justification . . . must not rely on

overbroad generalizations about the different talents,

capacities, or preferences of males and females,” id. at 533.

Here, it is undisputed that the State’s asserted interests in

ensuring competitive fairness, student safety, and equal

athletic opportunities for women and girls are important

governmental objectives. The question is whether the

44 DOE V. HORNE

transgender ban is substantially related to the achievement

of these objectives.

Four decades ago, we addressed whether an Arizona

policy excluding cisgender boys from girls’ sports violated

the Equal Protection Clause. We upheld that policy because

it was substantially related to the state’s objectives in

“redressing past discrimination against women in athletics

and promoting equality of athletic opportunity between the

sexes.” Clark I, 695 F.2d at 1131. We reached that

conclusion because: (1) “boys’ overall opportunity” to play

school sports was “not inferior to girls’”; (2) “males would

displace females to a substantial extent” if cisgender boys

were allowed to play on girls’ teams; and (3), most

importantly, “average physiological differences” between

boys and girls “allow[ed] gender to be used as . . . an

accurate proxy” for athletic ability and competitive

advantage. Id. (emphasis added). None of these conditions

is present here. 12

First, the Act does not afford transgender women and

girls equal athletic opportunities. The Act permits cisgender

women and girls to play on any teams, male or female, while

transgender women and girls are permitted to play only on

male teams. The Act also permits all students other than

transgender women and girls to play on teams consistent

with their gender identities; transgender women and girls

alone are barred from doing so. This is the essence of

discrimination. See Bostock v. Clayton County, 590 U.S.

644, 657 (2020) (“To ‘discriminate against’ a person . . .

12

As we noted in Hecox II, Clark I is also distinguishable from this case

because the policy challenged in Clark I adversely affected cisgender

boys, a historically favored group, rather than transgender women and

girls, a historically disfavored minority. Hecox II, 104 F.4th at 1082.

DOE V. HORNE 45

mean[s] treating that individual worse than others who are

similarly situated.”).

Although the Act allows transgender women and girls to

play male sports, the district court found that Plaintiffs

“cannot play on boys’ sports teams.” Doe, 683 F. Supp. 3d

at 968. The court reasoned that Plaintiffs have “athletic

capabilities like other girls [their] age,” that they would find

playing on boys’ teams “humiliating and embarrassing,” and

that “playing on a boys’ sports team and competing against

boys would directly contradict [their] medical treatment for

gender dysphoria and jeopardize [their] health.” Id. at 968–

69. In fact, the court found that “[p]articipating in sports on

teams that contradict one’s gender identity is equivalent to

gender identity conversion efforts, which every major

medical association has found to be dangerous and

unethical.” Id. (quoting Hecox I, 479 F. Supp. 3d at 977).

As we explained in Hecox II, “[t]he argument . . . that the

Act does not discriminate against transgender women

because they can . . . play on men’s teams is akin to the

argument we rejected in Latta[] that same-sex marriage bans

do not discriminate against gay men because they are free to

marry someone of the opposite sex.” 104 F.4th at 1083

(citing Latta, 771 F.3d at 467). 13

13

The generally accepted medical practice is to treat people who suffer

from gender dysphoria with “necessary, safe, and effective” gender-

affirming medical care. Doe, 683 F. Supp. 3d at 957. “The goal of

medical treatment for gender dysphoria is to alleviate a transgender

patient’s distress by allowing them to live consistently with their gender

identity.” Id. at 958. This treatment, “commonly referred to as

‘transition,’” includes “one or more of the following components:

(i) social transition, including adopting a new name, pronouns,

appearance, and clothing, and correcting identity documents;

(ii) medical transition, including puberty-delaying medication and

46 DOE V. HORNE

Second, the record does not demonstrate that transgender

females would displace cisgender females to a substantial

extent if transgender females were allowed to play on female

teams. As the district court noted in distinguishing Clark I,

“[i]t is inapposite to compare the potential displacement [of]

allowing approximately half of the population (cisgender

men) to compete with cisgender women, with any potential

displacement one half of one percent of the population

(transgender women) could cause cisgender women.” Doe,

683 F. Supp. 3d at 961 (footnote omitted) (quoting Hecox I,

479 F. Supp. 3d at 977). In the dozen or so years before

adoption of the Act, the AIA approved just seven

transgender students to play on teams consistent with their

gender identities—a tiny number when compared to the

roughly 170,000 students playing school sports in Arizona

each year. Id. During legislative hearings, proponents of the

Act were unable to cite a single instance of a transgender girl

displacing a cisgender girl on a girls’ sports team in Arizona.

Third, after carefully considering the extensive expert

evidence in the preliminary injunction record, the district

court found that a student’s transgender status is not an

accurate proxy for average athletic ability or competitive

advantage. As noted, the district court cited “the scientific

consensus” that “the biological cause of average differences

in athletic performance between men and women is . . . the

presence of circulating levels of testosterone beginning with

male puberty,” Doe, 683 F. Supp. 3d at 964, and that “[t]he

biological driver of average group differences in athletic

hormone-replacement therapy; and (iii) for adults, surgeries to alter the

appearance and functioning of primary- and secondary-sex

characteristics.” Id. “For social transition to be clinically effective, it

must be respected consistently across all aspects of a transgender

individual’s life.” Id.

DOE V. HORNE 47

performance between adolescent boys and girls is the

difference in their respective levels of testosterone, which

only begin to diverge significantly after the onset of

puberty,” id. at 968.

Contrary to the expert opinion evidence relied upon by

the district court, the Act applies to all transgender women

and girls, including those who the district court found do not

have an average athletic advantage over cisgender women

and girls. The district court found that, “[b]efore puberty,

there are no significant differences in athletic performance

between boys and girls,” id., yet the ban applies to

transgender kindergartners who are too young to have

experienced male puberty. Although prepubertal boys

sometimes outperform prepubertal girls on school-based

fitness testing, the district court found “no basis . . . to

attribute those small differences to physiology or anatomy

instead of” sociological factors. Id. at 966.

The categorical ban includes transgender women and

girls, such as Plaintiffs, who receive puberty blockers and

hormone therapy and never experience male puberty. The

district court found that “[t]ransgender girls who receive

puberty-blocking medication do not have an athletic

advantage over other girls because they do not undergo male

puberty and do not experience the physiological changes

caused by the increased production of testosterone

associated with male puberty.” Id. at 968. The court also

found that “[t]ransgender girls who receive hormone therapy

after receiving puberty-blocking medication will develop the

skeletal structure, fat distribution, and muscle and breast

development typical of other girls,” and “will typically have

48 DOE V. HORNE

the same levels of circulating estrogen and testosterone as

other girls.” Id. 14

Given these well-supported factual findings, the district

court properly concluded that Appellants are unlikely to

establish that the Act’s sweeping transgender ban is

substantially related to achievement of the State’s important

governmental objectives in ensuring competitive fairness

and equal athletic opportunity for female student-athletes.

The Act’s transgender ban applies not only to all transgender

women and girls in Arizona, regardless of circulating

testosterone levels or other medically accepted indicia of

competitive advantage, but also to all sports, regardless of

the physical contact involved, the type or level of

competition, or the age or grade of the participants.

Heightened scrutiny does not require narrow tailoring, but it

does require a substantial relationship between the ends

sought and the discriminatory means chosen to achieve

them. See Virginia, 518 U.S. at 533. Appellants have not

made that showing here.

We recognize that the research in this field is ongoing

and that standards governing transgender participation in

sports are evolving. In the last few years alone, both the

NCAA and International Olympic Committee have

14

The Act also includes transgender women and girls who have gone

through male puberty but receive gender-affirming hormone therapy to

suppress their circulating testosterone levels. Dr. Shumer testified that

“studies on transgender women who have undergone testosterone

suppression as adults . . . show that testosterone suppression resulted in

significant mitigation of muscle mass and development in adult

transgender women.” See Shumer Rebuttal Decl. ¶¶ 17–18. These

transgender women do not appear to have a competitive athletic

advantage. See id. ¶ 19 (citing Joanna Harper, Race Times for

Transgender Athletes, 6 J. Sporting Cultures & Identities 1 (2015)).

DOE V. HORNE 49

tightened their transgender eligibility policies—although

neither organization has adopted anything like Arizona’s

categorical ban on transgender females participating in

female sports. Legislatures are not prohibited from acting

“in the face of medical uncertainty,” Carhart, 550 U.S. at

166, and “[l]ife-tenured federal judges should be wary of

removing a vexing and novel topic of medical debate from

the ebbs and flows of democracy by construing a largely

unamendable Constitution to occupy the field,” L.W. ex rel.

Williams v. Skrmetti, 83 F.4th 460, 471 (6th Cir. 2023), cert.

granted, 2024 WL 3089532 (U.S. June 24, 2024) (No. 23-

477). But neither Carhart nor Skrmetti applied heightened

scrutiny, as we are obliged to do, and that standard requires

the State to demonstrate an “exceedingly persuasive

justification” for a discriminatory classification, without

relying on “overbroad generalizations about the different

talents, capacities, or preferences of males and females.”

Virginia, 518 U.S. at 531, 533. 15 The district court was

bound to rule on Plaintiffs’ request for limited injunctive

relief based on the evidence in the record before it. To be

sure, future cases may have different outcomes if the

evolving science supports different findings. But the court

did not have the luxury of waiting for further research to be

conducted; “we cannot avoid the duty to decide an issue

squarely presented to us.” United States v. Booker, 375 F.3d

508, 513 (7th Cir. 2004), aff’d, 543 U.S. 220 (2005).

We reject Appellants’ argument that the Act survives

intermediate scrutiny because it directly advances the State’s

15

See Carhart, 550 U.S. at 166 (addressing whether the challenged law

was “rational and in pursuit of legitimate ends”); Skrmetti, 83 F.4th at

486 (applying rational basis review to an equal protection challenge to

state laws prohibiting doctors from providing gender-affirming medical

care to minors).

50 DOE V. HORNE

objectives “roughly 99.996 percent of the time.” Reply Br.

at 26. In Appellants’ view, even if the ban does not directly

advance the State’s legitimate objectives as applied to

transgender women and girls who have not experienced male

puberty, such as Plaintiffs, the Act is substantially related to

the State’s interests because it advances legitimate State

interests as applied to cisgender men and boys, who make up

the vast majority of students affected by the legislation.

Because, as noted, the Act does not actually affect cisgender

men and boys, this argument is unpersuasive. 16

So, too, is Appellants’ argument that the Act satisfies

heightened scrutiny because it directly advances the State’s

objectives as applied to some transgender female athletes—

those who have experienced male puberty and who have not

received hormone therapy to suppress their levels of

circulating testosterone. Appellants correctly point out that

“[n]one of [the Supreme Court’s] gender-based

classification equal protection cases have required that the

statute under consideration must be capable of achieving its

ultimate objective in every instance.” Tuan Anh Nguyen v.

INS, 533 U.S. 53, 70 (2001). But the State does not carry its

burden by showing that a classification is capable of

achieving its ultimate objective in some circumstances.

Heightened scrutiny requires that the means adopted by the

State must be “in substantial furtherance of important

governmental objectives.” Id. (emphasis added). Moreover,

the Act’s practical effect is to displace the existing AIA and

NCAA policies which already limit the participation of

16

Because Plaintiffs do not challenge the Act’s sex classification, the

question presented is simply whether “excluding transgender girls from

girls sports teams” is substantially related to important governmental

interests, not whether excluding all “students of the male sex” from such

sports is justified. See B.P.J., 98 F.4th at 559.

DOE V. HORNE 51

transgender athletes based in part on levels of circulating

testosterone.

B.

The district court concluded that Plaintiffs were likely to

succeed not only on their equal protection claim but also on

their Title IX claim. Doe, 683 F. Supp. 3d at 974–75.

Appellants challenge this conclusion, arguing that Title IX

is unenforceable in this case because the State lacked clear

notice that excluding transgender women and girls from

female sports violates the statute. See Arlington Cent. Sch.

Dist. Bd. of Educ. v. Murphy, 548 U.S. 291, 296 (2006)

(“Congress has broad power to set the terms on which it

disburses federal money to the States, but when Congress

attaches conditions to a State’s acceptance of federal funds,

the conditions must be set out ‘unambiguously.’” (citations

omitted) (quoting Pennhurst State Sch. & Hosp. v.

Halderman, 451 U.S. 1, 17 (1981))).

Although not addressed by the district court, this is a

colorable argument because Title IX regulations permit

schools to “operate or sponsor separate teams for members

of each sex,” 34 C.F.R. § 106.41(b), and it may not have

been clear to the State when it accepted federal funding that

this provision does not authorize distinctions based on

assigned sex. Cf. Adams ex rel. Kasper v. Sch. Bd. of St.

Johns Cnty., 57 F.4th 791, 815–16 (11th Cir. 2022) (en banc)

(“Under the Spending Clause’s required clear-statement

rule, the School Board’s interpretation that [Title IX’s]

bathroom carve-out[, 34 C.F.R. § 106.33,] pertains to

biological sex would only violate Title IX if the meaning of

‘sex’ unambiguously meant something other than biological

52 DOE V. HORNE

sex, thereby providing the notice to the School Board that its

understanding of the word ‘sex’ was incorrect.”). 17

We need not address this issue at this time. Because

Secretary Horne (the only party formally enjoined by the

preliminary injunction, see Doe, 683 F. Supp. 3d at 977) was

properly enjoined based on the district court’s conclusion

that Plaintiffs are likely to succeed on the merits of their

equal protection claim, we need not decide whether

Plaintiffs are likely to succeed on the merits of their Title IX

claim as well. The district court should address the Spending

Clause issue in the first instance if raised in further

proceedings. We express no opinion on how the issue

should be resolved.

V.

Having determined that the district court did not err by

concluding that Plaintiffs are likely to succeed on their equal

protection claim, we turn to whether the district court abused

its discretion in addressing the remaining preliminary

injunction factors.

A.

Plaintiffs seeking a preliminary injunction must establish

that they are likely to suffer irreparable harm in the absence

of relief. Johnson, 572 F.3d at 1078. Appellants argue that

17

The Department of Education has proposed an amendment to

§ 106.41(b) that would clarify that Title IX does not authorize the

categorical exclusion of transgender female students from female sports.

See Nondiscrimination on the Basis of Sex in Education Programs or

Activities Receiving Federal Financial Assistance: Sex-Related

Eligibility Criteria for Male and Female Athletic Teams, 88 Fed. Reg.

22,860 (proposed Apr. 13, 2023) (to be codified at 34 C.F.R.

§ 106.41(b)(2)).

DOE V. HORNE 53

“Plaintiffs’ claim of irreparable harm is inconsistent with

their delay in seeking injunctive relief,” because “[n]early a

year passed . . . before they challenged” the Act. Opening

Br. at 67. See Oakland Trib., Inc. v. Chron. Pub. Co., 762

F.2d 1374, 1377 (9th Cir. 1985) (“Plaintiff’s long delay

before seeking a preliminary injunction implies a lack of

urgency and irreparable harm.”); see also Garcia v. Google,

Inc., 786 F.3d 733, 746 (9th Cir. 2015) (en banc) (noting that

delay can undercut a claim of irreparable harm).

We disagree. Plaintiffs sought preliminary injunctive

relief just seven months after the Act took effect. This was

not a long delay in this context, and even if it were, “delay is

but a single factor to consider in evaluating irreparable

injury,” and “‘courts are loath to withhold relief solely on

that ground.’” Arc of California, 757 F.3d at 990 (quoting

Lydo Enters., Inc. v. City of Las Vegas, 745 F.2d 1211, 1214

(9th Cir. 1984)). Furthermore, even a long delay “is not

particularly probative in the context of ongoing, worsening

injuries.” Id. 18

Appellants argue that Plaintiffs fail to show irreparable

harm because their “claims of harm stem from their gender

dysphoria diagnosis” rather than the Act. Opening Br. at 68.

This misunderstands Plaintiffs’ claims. It is Plaintiffs’

gender identity, not their gender dysphoria, that causes them

18

Jane was not affected by the transgender ban during the 2023-24

school year. She played soccer on club and recreational teams, which

were not subject to the ban. See Ariz. Rev. Stat. § 15-120.02(A)

(applying only to school-sponsored sports); Doe, 683 F. Supp. 3d at 959.

Megan was affected by the ban in 2023-24; she was a member of the

girls’ volleyball team at the Gregory School and was allowed to practice

with the team but barred from playing in games. Doe, 683 F. Supp. 3d

at 962. Megan would have been irreparably harmed were she barred

from playing in games for a second school year.

54 DOE V. HORNE

to wish to play on girls’ teams, and it is the Act, not their

medical condition, that prevents them from doing so. In any

event, we ordinarily will not consider arguments raised for

the first time on appeal. 19

B.

Appellants argue that the final two preliminary

injunction factors—the balance of the equities and the public

interest—favor the denial of preliminary injunctive relief

because “Plaintiffs will displace biological female athletes”

if they are allowed to play on girls’ teams. Opening Br. at

69. The record, however, shows that “Megan’s teammates,

coaches, and school are highly supportive of her and would

welcome her participation on the girls’ volleyball team,”

Doe, 683 F. Supp. 3d at 960, and that “Jane’s teachers,

coaches, friends, and members of her soccer team have all

been supportive of Jane’s identity,” id. at 959. Appellants

19

Appellants point out that “it is claims that are deemed waived or

forfeited, not arguments.” United States v. Blackstone, 903 F.3d 1020,

1025 n.2 (9th Cir. 2018) (quoting United States v. Pallares-Galan, 359

F.3d 1088, 1095 (9th Cir. 2004)); see Exxon Shipping Co. v. Baker, 554

U.S. 471, 487 (2008) (“[O]nce a federal claim is properly presented, a

party can make any argument in support of that claim; parties are not

limited to the precise arguments they made below.” (quoting Yee v.

Escondido, 503 U.S. 519, 534 (1992))). But these decisions do not alter

our general rule that we ordinarily do not consider arguments raised for

the first time on appeal. See Exxon Shipping, 554 U.S. at 487 (“‘It is the

general rule, of course, that a federal appellate court does not consider

an issue not passed upon below,’ when to deviate from this rule being a

matter ‘left primarily to the discretion of the courts of appeals, to be

exercised on the facts of individual cases’” (citations omitted) (quoting

Singleton v. Wulff, 428 U.S. 106, 120–21 (1976))); Bolker v. Comm’r,

760 F.2d 1039, 1042 (9th Cir. 1985) (“As a general rule, we will not

consider an issue raised for the first time on appeal, although we have

the power to do so.”).

DOE V. HORNE 55

have not shown that Plaintiffs would displace other students.

In any case, “it is always in the public interest to prevent the

violation of a party’s constitutional rights.” Melendres, 695

F.3d at 1002 (quoting Sammartano, 303 F.3d at 974).

VI.

We hold that the district court did not abuse its discretion

by granting Plaintiffs’ motion for a narrow preliminary

injunction. We note that nothing in today’s decision, or in

the district court’s decision, precludes policymakers from

adopting appropriate regulations in this field—regulations

that are substantially related to important governmental

objectives. See Clark I, 695 F.2d at 1129. States have

important interests in inclusion, nondiscrimination,

competitive fairness, student safety, and completing the still

unfinished and important job of ensuring equal athletic

opportunities for women and girls, who must have an equal

opportunity not only to participate in sports but also to

compete and win. We hold only that the district court did

not abuse its discretion by enjoining Arizona from barring

Jane and Megan from playing school sports consistent with

their gender identity while this litigation is pending.

AFFIRMED.