Proposition 134: Male and Female Participation in School Sports

What does the measure do?

The measure requires that any school-based team or sport be explicitly designated as being:

for biological males only;

for biological females only;

coeducational or mixed.

Under the measure, students must compete on teams that match their biological sex or on a coeducational team. Biological females are allowed to participate on a team or sport designated for biological males if there is no equivalent female team offered for that sport. Participation on a coeducational or mixed team or sport is open to all. In addition, the measure prohibits any government entity, licensing or accrediting organization, or athletic association from investigating or penalizing a school for designating a team or sport as being only for biological females.

How does the measure define biological males and females?

The measure defines biological sex in terms of production of reproductive cells. "Male" is defined as children or adults whose biological reproductive system is organized around the production of sperm cells. "Female" is defined as children or adults whose biological reproductive system is organized around the production of ova, or egg cells. The measure does not impose a specific method for determining or demonstrating biological sex. Individual schools or school districts must determine their own verification procedures.

What teams does the measure apply to?

The measure applies to all teams and sports organized by schools or athletic associations, including teams that compete against other schools, in-house intramural sports, and after-school programs sponsored by schools. Schools include all public, charter, private, and religious school teams and sports from elementary through high school, and all public or private colleges, universities, and community colleges. Athletic associations are defined in the measure as organizations that administer extracurricular athletic competitions for schools. The measure does not apply to youth sports and leagues that operate separately from schools.

The governing body of every school or district must adopt a policy implementing the requirements established by the measure. For public K-12 schools, if a school district does not follow the measure's requirements, the state Commissioner of Education must first notify the district of its noncompliance. If the school district does not respond to this notification with a good-faith attempt to comply, then the commissioner must take corrective action. The measure does not establish an enforcement mechanism for private K-12 schools, colleges and universities, or athletic associations that do not adhere to the measure's requirements.

How does the measure interact with state and federal anti‑discrimination law?

The Colorado Anti-Discrimination Act (CADA) prohibits discrimination in employment, housing, and places of public accommodation based on a person's sex, sexual orientation, gender identity, and gender expression. Public K-12 schools, colleges, and universities may not exclude students from extracurricular activities that align with their gender identity, even if their gender identity is different from their biological sex. It is unclear at this time how the measure will impact current state law.

At the federal level, Title IX of the Education Amendments of 1972 prohibits sex-based discrimination in federally funded education programs. Courts and presidential administrations have interpreted Title IX in a variety of ways, sometimes including and sometimes excluding gender identity under the definition of "sex." On February 5, 2025, the President issued Executive Order 14201, "Keeping Men Out of Women's Sports," which directs federal agencies to interpret Title IX as prohibiting biological males from participating on teams or in sports designated as being for biological females. States that do not adhere to federal policy may face cuts in federal funding, and state laws or policies that conflict with federal law may face legal challenges from the federal government. At least seven Colorado schools and school districts have adopted policies restricting biological males who identify as female from participating in female sports. In June 2026, the U.S. Supreme Court ruled that Title IX permits states to adopt laws that maintain separate male and female sports based on biological sex.

How do athletic associations currently address this issue?

The Colorado High School Activities Association (CHSAA), the association that oversees high school sports, recognizes a right for transgender athletes to participate in school activities. Its rules allow CHSAA to review schools' athletic eligibility decisions for transgender students. In 2025, eight schools and school districts in Colorado filed a federal lawsuit challenging CHSAA rules and CADA requirements related to classification of sports teams by sex. The group of schools and districts and CHSAA reached a settlement agreement in December 2025 that allows schools to maintain separate sports teams and facilities for biological males and biological females without being penalized or sanctioned by CHSAA. However, the portion of the lawsuit challenging CADA is still ongoing.

At the collegiate level, the National Collegiate Athletic Association (NCAA) rules state that competing in female sports is limited to student athletes who are assigned female at birth, and student athletes assigned male at birth cannot receive athletic scholarships designed for females, regardless of their gender identity. The NCAA rules do not apply to intramural collegiate sports.