Colorado voters have approved a ballot measure that bans transgender children from playing on school sports teams that do not align with the sex they were assigned at birth. The Associated Press called the race for Proposition 134 at 4:12 p.m. Thursday, with 52% of votes in favor. The measure, which passed with a slim majority, adds language to state statute defining boys and girls based on physical anatomy and biological reproductive systems, effectively excluding transgender students from participating on teams matching their gender identity.
The initiative, championed by the group Protect Kids Colorado, will require schools and athletic associations that receive state funding to designate teams as male, female, or co-ed. Students assigned male at birth will be restricted to boys teams or co-ed teams, while those assigned female at birth will be limited to girls teams or co-ed teams. Transgender students will only be permitted to join co-ed teams under the new law. Schools must adopt policies to implement these requirements by January 1.
What Proposition 134 Does
Proposition 134 amends Colorado law to establish a strict definition of sex for athletic purposes. It defines a girl as “a person with female reproductive organs” and a boy as “a person with male reproductive organs.” Opponents say the definitions mean a school cannot rely on its own records or a student’s birth certificate to determine a child’s sex. The measure applies to all school-sponsored sports, from kindergarten through college, at any school or sports association that receives state funding.
The law contains a specific provision allowing boys teams to include female participants only if “no corresponding female team is offered for that sport.” However, the core of the measure is the segregation of students based on their assigned sex at birth for all gendered sports.
The Push for the Ban
The group’s leader, Erin Lee, a prominent anti-LGBTQ+ activist, celebrated the victory as a clear signal from voters. “People from every corner of our state gave what they could—time, treasure, courage and conviction—because our children are worth protecting,” Lee said in a statement. “And today, we are sending a clear signal to Colorado’s leadership: when elected officials fail or refuse to protect kids, We the People will come together and do it ourselves. Our voices cannot be ignored.”
The results, Lee said, “send a powerful political message that pushing gender ideology on children is a losing issue, voters are not in favor of men in women’s sports, and protecting kids is a great unifier. We’ve proven that these issues transcend party lines.”
Lee’s personal story was central to the campaign. She has spoken about her 12-year-old daughter being invited to a gender and sexuality awareness art club at her middle school, an experience she said led her daughter to believe, for about a year, that she was transgender. Protect Kids Colorado argued that such exposure and the participation of transgender athletes in girls’ sports were harmful to children. The group also backed two other ballot measures: Proposition 135, which would prohibit surgeries on minors for the purpose of altering sex characteristics, and Proposition 133, which mandates life imprisonment without parole for child sex traffickers.
The Opposition’s Response
Families Not Politics, an issue committee backed by LGBTQ+ advocacy organizations, acknowledged the passage of Proposition 134 and 135 but vowed to continue fighting for transgender youth. The committee, which includes organizations like One Colorado, Rocky Mountain Equality, and Planned Parenthood of the Rocky Mountains, warned that the measures would create significant barriers for transgender students.
“Colorado’s kids will have to live with the consequences of this election—they will face new barriers to medically necessary healthcare and new, expensive barriers and exclusion from full participation in school,” the Families Not Politics campaign said in a statement. “Their families will now have to navigate laws created by a political campaign that turned their children into a statewide controversy.” Opponents of the measure argued that its definitions could lead to invasive verification processes, including genital examinations, to determine a student’s eligibility for a sports team.
The campaign against the measures was heavily funded, with Families Not Politics raising approximately $3.5 million. Major donors included Planned Parenthood, the American Civil Liberties Union (ACLU), and Cobalt, an abortion rights organization. The opposition framed the fight as one of civil rights and the well-being of children.
Legislature Could Still Amend Proposition 134
As a statutory measure rather than a constitutional amendment, Proposition 134 could be subject to changes by the state legislature. Gov.-elect Phil Weiser, a Democrat, signaled a willingness to back legislative changes to Propositions 134 and 135.
Bruce Parker, the executive director of Rocky Mountain Equality, emphasized the uncertainty surrounding the law’s enforcement. The passage of the measures, he said, intentionally leaves basic questions about how they will be enforced unanswered. “To every transgender kid and family, we’ve got your back. This is your home too. This vote doesn’t change that,” Parker said in a statement. Families Not Politics has pledged to “exhaust every option” to defend the rights of transgender students.
The impact of Proposition 134 will begin to take shape in the coming months as schools develop new policies. The law’s practical application and its effect on transgender students’ lives and participation in school activities will be closely watched by advocates and opponents alike. The broader national conversation over the rights of transgender youth in sports and healthcare continues, with Colorado’s vote adding another chapter to the ongoing debate.
