Colorado voters approved two ballot measures restricting transgender students' participation in school sports and banning certain gender-affirming surgeries for minors.
The Associated Press called the sports measure Thursday and the surgery measure Friday. Opponents of both conceded defeat Thursday.
Proposition 134 requires school and college athletic teams to be designated male, female or coeducational. Students generally must compete on teams matching their sex assigned at birth, as defined by the measure, rather than their gender identity. Coeducational teams remain open to all students, and female athletes can join male teams if no equivalent female team is available.
Schools must adopt policies to implement the requirements, but the measure doesn't specify how they should verify students' sex.
Proposition 135 prohibits surgeries intended to alter minors' biological sex characteristics, with certain medical exceptions. It also prohibits government funding and insurance coverage for those procedures. It does not ban nonsurgical care such as puberty blockers, hormone therapy or counseling. Gender-affirming surgeries for transgender youth are rare in the U.S., according to a 2024 study published in JAMA Network Open.
The conservative group Protect Kids Colorado led the campaigns behind both measures. Supporters argued the sports restriction would protect fairness and safety, and that young people should wait until adulthood for surgery.
Opponents said the measures discriminate against transgender students and interfere with decisions that belong to families and doctors.
The results contrast with Democrats' sweep of Colorado's major statewide races.
Scott Skinner-Thompson is a law professor at the University of Colorado Boulder. He said that while the Front Range has largely shifted to the left, other parts of the state remain conservative.
"That has led to, you know, not just what appear to be the results on Propositions 134 and 135, but also routine litigation between legislatively enacted LGBTQ anti-discrimination laws and First Amendment free speech and freedom of religion lawsuits ending up before the Supreme Court," he said.
Skinner-Thompson had concerns about how the sports ballot measure would be enforced.
"This invasive, dehumanizing process will be potentially imposed, if the law is implemented, not just on trans kids, but on anybody who is gender divergent and doesn't comply with the norm," he said.
Erin Lee, who leads Protect Kids Colorado, said leaving verification to schools respects local control. She said schools could use a doctor's note, a cheek swab or an original birth certificate to determine eligibility.
"It is as simple as looking at a piece of paper to verify," she said.
Both propositions change state statutes, not the Colorado Constitution. That means, as Skinner-Thompson noted, that Colorado lawmakers could make changes to both ballot measures. They can be tweaked or overturned outright through a simple majority vote from the state legislature.
Gov.-elect Phil Weiser said Wednesday that state lawmakers would need to "take a long, hard look at what makes sense" in implementing the measures.
Lee said the ballot measures reflect what Coloradans want.
"If Phil Weiser intends to use the legislature to undermine the same democratic process that elected him, that's his decision," she said. "But he should absolutely be prepared to explain that to Colorado voters."
Between 52% and 53% of voters supported each ballot measure.
Both will take effect Jan. 1.
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