A ballot measure heading to Colorado voters would bar athletes assigned male at birth from taking part in female school sports programs. Proposition 134 — titled "Male and Female Participation in School and Collegiate Sports" — puts before voters a measure that would bar athletes assigned male at birth from taking part in athletic competitions designated for female participants, covering everything from intramural activities within schools to competitive high school and intercollegiate programs.
Youth sports programs and leagues that run independently of schools fall outside the scope of the measure, as set out in the 2026 State Ballot Information Booklet — the document commonly referred to as the blue book.
Under the proposed rule, school athletic programs would be required to classify every sport as open to male students, female students, or both, with male students permitted to enter only those categories designated for males or listed as coed. Under the ballot measure, any girl or woman would be permitted to join a male-designated team in cases where no corresponding female roster exists for that sport.
Under the proposed measure, schools designated exclusively for female athletes would be shielded from any inquiry or disciplinary action by oversight bodies — including government agencies, licensing or accreditation authorities, and athletic associations.
Voters are scheduled to head to the polls on the third day of November.
The measure put before voters as Proposition 134 would amend Colorado statutes to establish new rules governing athletic participation at both K–12 and college levels, sorting eligibility by sex as defined through specified aspects of a person's biological reproductive anatomy. Under the proposal, each school, higher-education institution, or athletic association would be required to classify every team and intramural sport as either male, female, or coeducational, with participants generally limited to competing in the category matching their designated sex or on a coeducational squad, though a female athlete would be permitted to join a male-designated team when no comparable female option exists. The measure would further bar government bodies, licensing or accrediting organizations, and athletic associations from filing complaints, launching investigations, or pursuing other adverse actions against schools that maintain sex-separated teams, and it would vest enforcement authority for K–12 districts in the state commissioner of education.
Voters placed Proposition 134 on the ballot by gathering the required petition signatures.
Approval of Proposition 134 would obligate schools, school districts, and athletic associations to classify every sports team as open to either male athletes, female athletes, or both combined — and to put in place rules barring athletes assigned male at birth from participating on teams designated for female athletes. Under the measure as written, girls and women would be permitted to join teams designated for male athletes only when no equivalent girls' or women's team existed for that sport.
Defeating Proposition 134 at the ballot box would leave individual schools, districts, and athletic associations free to govern their own eligibility rules, provided those rules remain within the boundaries already drawn by state and federal law. Under Proposition 134, approval hinges on tallying more than half of all ballots cast in its favor.
