Voters in four states will decide on Tuesday on ballot measures that could significantly impact the participation of transgender athletes in sports. Arizona and Nebraska already have laws restricting biological males from competing in female sports, and voters in these states will consider measures to expand or strengthen these existing rules. Washington and Colorado, which do not currently have statewide sex-based restrictions, could establish them if these measures pass.
Washington: Initiative 638
A "yes" vote on Washington's Initiative 638 would prohibit students defined as biologically male from competing in girls' K-12 interscholastic sports. Eligibility would require documentation verifying biological sex based on factors like reproductive anatomy, genetic makeup, or testosterone levels. Current rules in Washington allow athletes to compete based on gender identity. Opponents argue the initiative would discriminate against transgender students and could lead to invasive examinations. Supporters counter that biological sex can be verified through existing sports physicals or a simple cheek swab and that claims of invasive exams are fearmongering. Polling data suggests a 64% market-implied probability of Initiative 638 passing.
Colorado: Proposition 134
Colorado's Proposition 134 would implement statewide sex-based participation requirements for school sports from K-12 through college, generally requiring athletes to compete on teams matching their biological sex. The measure defines females as individuals with biological systems organized for ova production and males for sperm production. Unlike Washington's initiative, it does not mandate specific verification methods, leaving schools to establish their own policies. Opponents raise concerns about government overreach and potential gender checks, while proponents, including Jennifer Sey, chair of the campaign supporting Proposition 134, note that many states with similar restrictions do not require invasive examinations. There is a 55% market-implied probability of Proposition 134 passing.
Arizona: Proposition 318
Arizona's Proposition 318 aims to expand existing restrictions on public school sports to include private schools and athletic associations. It would also mandate that schools and associations restrict access to athletic facilities like restrooms and locker rooms based on biological sex as recorded on an original birth certificate. Athletes would be permitted to sue schools and associations for knowingly violating the law. The measure would retain protections for athletes on coed teams and allow girls to compete on boys' teams if no equivalent girls' team exists. Opponents, including the ACLU, argue the proposition singles out transgender students and could lead to intrusive questioning and lawsuits. Supporters contend it closes loopholes, enhances privacy and safety, and ensures fair competition. Proposition 318 has an 82% market-implied probability of passing.
Nebraska: Initiative 442
Nebraska's Initiative 442 seeks to amend the state's constitution to prohibit biological males from competing in girls' and women's school sports at all levels. Teams would be designated as male, female, or coed, with female teams exclusively for biological females. This measure would apply to public and private institutions whose teams compete against public schools. Nebraska already has the Stand With Women Act, signed into law in June 2025, which restricts biological males in female sports. However, Initiative 442 would embed these restrictions in the state constitution, making them more difficult to overturn. Opponents argue the amendment is discriminatory and unnecessary given the existing law, while supporters believe constitutional protection is essential to safeguard female athletes' opportunities and safety. No market prediction is currently available for this initiative.