Voters in four states will decide Tuesday whether to change rules governing who can compete in girls’ and women’s sports. Some proposals would also affect access to locker rooms and other private spaces.
Arizona and Nebraska already limit biological males’ participation in female sports. A yes vote in either state would strengthen or broaden those restrictions. Washington and Colorado have no comparable statewide rules in place. Approval there would introduce new restrictions for school sports in two traditionally Democratic states.
Here’s what each measure would do, what supporters and opponents argue, and how prediction markets viewed the proposals at the time of writing.
Washington
What a yes vote would do: Bar students defined as biologically male from competing in girls’ K-12 school sports. Girls would need to provide documentation from a health professional confirming their biological sex, based on reproductive anatomy, genetic makeup or naturally produced testosterone levels.
Under current rules, Washington K-12 athletes can compete according to their gender identity. Earlier this year, a boy in Camas switched to the girls’ team during the season.
What a no vote would do: Keep the existing eligibility rules and make no changes to how a student’s eligibility is assessed.
What opponents say: Groups including No Hate in Washington State say the measure would discriminate against transgender students and could lead to invasive genital examinations for girls.
Supporters reject that concern as fearmongering. They say biological sex can be confirmed during a routine sports physical, which many high school athletes already receive. They also point to cheek swabs, which collect DNA from inside the mouth, as another possible method.
Prediction market estimate at the time of writing: A 64% implied chance that Initiative 638 would pass.
Colorado
What a yes vote would do: Set statewide sex-based participation rules for school sports, from K-12 through college. In general, athletes would play on teams that match their biological sex. Exceptions would allow coed teams and girls to join boys’ teams when no equivalent girls’ team is available.
The proposal would cover public, charter and private schools, along with colleges and universities. It would apply to interscholastic and intramural sports, including school-sponsored clubs.
Proposition 134 defines females as people whose reproductive systems are organized around producing ova, and males as people whose systems are organized around producing sperm.
The measure does not specifically require a doctor’s note or medical exam to establish biological sex. Instead, schools would set their own eligibility policies, and the proposal does not prescribe a method of verification. The state education commissioner could act against districts that deliberately fail to comply.
What a no vote would do: Leave the current system in place, allowing schools, districts and athletic associations to set their own participation rules, subject to state and federal law.
What opponents say: Planned Parenthood and other critics argue that Proposition 134 represents government overreach and could result in invasive gender checks for girls.
Jennifer Sey, founder of XX-XY Athletics and chair of the campaign backing the measure, counters that 27 states already restrict biological males from girls’ sports. She has argued that the invasive examinations opponents warn about are not taking place in those states.
Prediction market estimate at the time of writing: A 55% implied chance that Proposition 134 would pass.
Arizona
What a yes vote would do: Expand Arizona’s existing rules for public school sports to include private schools and athletic associations, including organizations overseeing youth and college sports. It would also require schools and athletic associations to limit access to athletic restrooms, locker rooms and other private spaces according to biological sex as listed on an original birth certificate.
Athletes could sue schools or athletic associations that knowingly violate the law. The measure would preserve protections for coed teams and would not categorically bar girls from playing on boys’ teams.
What a no vote would do: Keep the current public school restrictions but not extend them to additional institutions or add the proposed rules for private spaces.
What opponents say: Civil rights organizations, including the ACLU, argue that Proposition 318 targets transgender students, could lead to intrusive questions about girls’ biological sex and expose schools to costly lawsuits.
Supporters say the measure would close gaps in existing law, protect privacy and safety in locker rooms and bathrooms, and set consistent standards for fair competition.
Prediction market estimate at the time of writing: An 82% implied chance that Proposition 318 would pass.
Nebraska
What a yes vote would do: Amend the state constitution to bar biological males from competing in girls’ and women’s school sports, from K-12 through college. Schools would designate teams as male, female or coed, with female teams reserved for biological females.
The amendment would apply to public schools and colleges, as well as private institutions whose teams compete against public schools.
Nebraska already restricts biological males from competing in girls’ and women’s sports under a law signed by Gov. Jim Pillen in June 2025. The ballot measure would place those restrictions in the state constitution, making them more difficult for future lawmakers to repeal.
What a no vote would do: Leave the constitution unchanged. The existing law would remain in effect.
What opponents say: OutNebraska and the Fairness for All campaign argue that the amendment would discriminate against transgender students and that putting the restrictions in the constitution is unnecessary when a law already exists. They also note that transgender athletes represent a very small share of Nebraska’s population.
Supporters say constitutional protections would guard against future changes to state law. The Fairness for Girls campaign argues that allowing biological males to compete against girls raises safety concerns and can cost female athletes medals, advancement opportunities and scholarships.
Prediction market estimate at the time of writing: No Polymarket estimate was available.
