Male and Female Participation in School and Collegiate Sports
School and college teams must be designated by biological sex, with each school deciding how to verify it.
Cheat sheet The whole measure in 30 seconds tap to open
All school-based athletic teams must be designated for biological males, biological females, or as mixed, and schools and districts must adopt sex-eligibility policies.
Schools, districts and athletic associations may keep setting their own eligibility policies under current state and federal law.
Strongest case for
Females should compete against females; biological males on girls' teams gain an unfair advantage and can cost female athletes wins, records, podium spots and scholarships.
Strongest case against
It turns athletic eligibility into a body inspection and creates new grounds for discrimination, potentially affecting many athletes, not only transgender ones.
Watch out: It sets a standard with no verification method, and the Blue Book says outright that it is 'unclear at this time' how the measure interacts with the Colorado Anti-Discrimination Act. Enforcement is specified only for public K-12 - there is none for private K-12, colleges, or athletic associations.
What this actually does
Every school-based team or sport, from elementary school through college, would have to be labeled male-only, female-only, or mixed, based on biological sex - defined by whether a person's reproductive system is organized around producing sperm or eggs. Students compete on the team matching their biological sex, or on a mixed team. Girls may play on a boys' team if no girls' equivalent exists. The measure does not specify how a school should verify sex; each school or district decides. Schools also could not be investigated or penalized for designating a team female-only.
What your vote means
All school-based athletic teams must be designated for biological males, biological females, or as mixed, and schools and districts must adopt sex-eligibility policies.
Schools, districts and athletic associations may keep setting their own eligibility policies under current state and federal law.
On every measure, yes means change something and no means leave it alone.
Easiest thing to get wrong
Read this twice
It sets a standard with no verification method, and the Blue Book says outright that it is 'unclear at this time' how the measure interacts with the Colorado Anti-Discrimination Act. Enforcement is specified only for public K-12 - there is none for private K-12, colleges, or athletic associations.
The case each side makes
Straight from the state's official booklet, shortened. These are arguments as each side makes them — not findings of fact, and not our view.
Why people say yes
- Females should compete against females; biological males on girls' teams gain an unfair advantage and can cost female athletes wins, records, podium spots and scholarships.
- A single statewide standard ends the current patchwork, under which female athletes compete under different rules depending on where they live.
- Physical differences in strength, stature, lung capacity and growth affect safety and injury risk, and shared locker rooms raise privacy concerns.
Why people say no
- It turns athletic eligibility into a body inspection and creates new grounds for discrimination, potentially affecting many athletes, not only transgender ones.
- Because it mandates a standard but no verification method, each school invents its own - so some athletes face invasive or expensive testing while others just bring a doctor's note, and athletes could be singled out based on appearance, strength or success.
- School sports should build confidence and belonging; forcing kids onto teams that do not match their gender identity leads to harassment, shame and isolation, and the rules reach even young children who are not competing for championships or scholarships.
Where this sits politically
high confidence Filed by Protect Kids Colorado as part of a three-measure package. Opposed by One Colorado, Planned Parenthood Action Fund and the Rose Community Foundation with a roughly 9-to-1 money advantage. Transgender participation in school sports is one of the sharpest partisan dividing lines in current American politics.
How we place the needle and why it is an estimate, not a measurement
We read four things, all of them public and documented:
- Who filed it and what they are affiliated with.
- The recorded party vote, where one exists. On this ballot only Proposition NN has one, because it is the only measure the legislature referred.
- Which side of the political infrastructure is paying for each campaign.
- Which direction the policy moves compared with current law.
Confidence is high when all four point the same way and low when they contradict each other. A low-confidence needle is telling you the measure genuinely does not sort neatly — Amendment 86 is the clearest case, with conservative sponsors and anti-gerrymandering content.
This is our editorial read, not a measurement. A citizen initiative has no party sponsor, so for 13 of these 14 measures there is no official partisan label to report — only inference. Use the needle to get oriented, then read the measure and decide for yourself.
What it costs
Mostly administrative and indeterminate. Added workload and legal costs for the Department of Education if a district intentionally refuses to comply; colleges and universities absorb policy-update costs from tuition, fees or athletic revenue; minimal costs for schools and districts to write and apply policies.
Who it touches: Student athletes from elementary school through college at public, charter, private and religious schools, plus schools, districts and athletic associations.
Who put it on your ballot
Conservative
People who filed it
Campaigning for it
Campaigning against it
Individual donors named in filings
Brought as a package with 133 and 135 by Protect Kids Colorado.
Who is paying for the ads
Money for it
Money against it
What the money tells you
The lopsided one. Opponents have roughly a 9-to-1 money advantage, and the $160,000 on the yes side is shared across three measures.
Figures are a late-September 2026 snapshot from TRACER campaign-finance filings and will have moved since. A committee marked slate spreads one total across several measures — do not read its number as spending on this measure alone.
Questions people ask
Common questions (6)
The things people want to know before they vote, answered from primary sources where they exist. Every answer was drafted with AI assistance from retrieved documents, then read and approved by a person. Figures carry the year they refer to.
How many transgender students currently play school or college sports in Colorado?
There is no official count of how many transgender students currently play school or college sports in Colorado. The Colorado High School Activities Association, which governs the state's high school athletics, does not track the participation of transgender athletes. Individual school districts and colleges also do not publish these counts.
Because official data does not exist, both sides of Proposition 134 frame the unknown number differently. Opponents of the measure emphasize that the statewide number of transgender athletes is very small. They argue that the initiative unnecessarily targets a tiny minority of students and that schools should continue handling eligibility under current laws.
Supporters of the measure argue that a statewide policy is necessary to guarantee fair competition and protect the physical safety of female athletes. They maintain that separate sports teams are important regardless of how many transgender students are currently playing.
The lack of tracking has led to conflicting claims. In 2026, the federal Department of Education claimed that up to 61 biological males might occupy roster spots on girls' teams in Jefferson County Public Schools. The school district denied the claim, stating the actual number was zero.
What do the main medical and sports governing bodies say about transgender athletes, and which states have passed similar laws?
Major medical groups oppose bans and mandatory testing for transgender athletes, while top sports governing bodies have recently restricted transgender women from female categories, and 29 states have passed bans.
The American Medical Association opposes mandatory medical treatments, surgery, or specific hormonal guidelines for transgender athletes. The American Academy of Pediatrics opposes blanket bans on transgender youth in sports, stating that exclusion harms their mental health.
Conversely, major sports organizations have recently tightened their rules. * In February 2025, the NCAA banned transgender women from competing in women's college sports, though they may practice with women's teams. * In March 2026, the International Olympic Committee limited female events to biological females, determined by gene screening.
As of late 2026, tracking by the Movement Advancement Project shows 29 states ban transgender students from playing on school sports teams that match their gender identity. Twenty-seven states did this through legislation and two through state policy. In June 2026, the U.S. Supreme Court upheld state bans in Idaho and West Virginia.
Colorado currently allows schools and athletic associations to set their own eligibility policies. If passed, Measure 134 would align Colorado with the 29 states that require sports teams to be designated by biological sex.
What are the current state high school athletic association and NCAA eligibility policies regarding transgender student athletes?
The Colorado High School Activities Association (CHSAA) allows local school districts to set their own eligibility rules, while the NCAA restricts women's sports to athletes assigned female at birth.
At the high school level, CHSAA bylaws state that transgender athletes have a right to participate on teams matching their gender identity. However, the association leaves eligibility decisions up to individual schools and districts. Following a December 2025 lawsuit settlement, CHSAA agreed it will not penalize schools that require athletes to compete based on biological sex.
At the collegiate level, the NCAA updated its policy in February 2025. The rules restrict women's sports competitions to student-athletes assigned female at birth. Athletes assigned male at birth may not compete on women's teams, though they may practice with them. Men's teams remain open to all eligible student-athletes regardless of sex assigned at birth.
Supporters of Measure 134 argue that replacing local rules with a statewide biological sex requirement ensures fairness in female sports. Opponents argue the measure discriminates against transgender youth and that current CHSAA rules already give districts flexibility to manage eligibility.
How many transgender student athletes are currently participating in K-12 and collegiate sports within the state?
There is no official count of transgender student athletes participating in K-12 or collegiate sports in Colorado.
The Colorado High School Activities Association (CHSAA), which oversees K-12 athletics, does not track the number of transgender athletes. Individual school districts have also stated they do not collect or publish data on how many students play on teams that differ from their biological sex. At the collegiate level, universities and athletic conferences similarly do not publish statewide participation counts for transgender athletes.
Because there are no official statistics, it is difficult to know exactly how many students Measure 134 would affect. Supporters of the measure argue it is necessary to ensure competitive fairness and protect athletic opportunities for biological females, regardless of how many transgender students are currently participating. Opponents argue that without evidence of widespread participation, the measure is an unnecessary ban that discriminates against a small number of students.
Under current CHSAA policy, transgender students can participate in sports free from unlawful discrimination. However, because CHSAA leaves specific eligibility rules to local control, some individual school districts have recently adopted their own policies restricting participation based on biological sex.
How many other states have passed similar laws requiring school sports teams to be designated by biological sex?
As of 2026, 27 states have passed laws requiring school sports teams to be designated by biological sex, and two additional states have similar agency regulations.
According to the Movement Advancement Project and Ballotpedia, 27 states have enacted these laws since 2020. Two other states, Alaska and Virginia, enforce similar rules through state regulations or agency policies. The remaining 21 states, including Colorado, do not have such laws. In Colorado, transgender participation is currently allowed through policies set by the state high school athletic association.
In June 2026, the U.S. Supreme Court ruled that states are permitted to separate school sports teams based on biological sex. The decision upheld state laws in West Virginia and Idaho, though it does not require states to pass such bans.
Supporters of these laws argue that biological differences give male-assigned athletes an unfair advantage, and that sex-based categories preserve fair competition and safety in girls' sports. Opponents argue that blanket bans are poorly written, single out vulnerable children, and deny transgender youth the educational and social benefits of participating in school athletics.
If voters approve Measure 134, Colorado will join the states with a statutory requirement for sex-designated sports teams.
How does this measure interact with current federal Title IX guidelines regarding sex discrimination in educational programs?
Proposition 134 aligns with the current federal interpretation of Title IX, the 1972 civil rights law prohibiting sex-based discrimination in schools.
In September 2026, the U.S. Department of Education formally rescinded a 2024 rule that had extended Title IX protections to cover gender identity. The department reinstated 2020 regulations and currently interprets Title IX as requiring sports teams to be separated by biological sex.
This federal stance has already impacted Colorado. In June 2026, the Department of Education issued a warning to Jefferson County Public Schools, threatening to withhold federal funding because the district allowed transgender girls to play on female sports teams.
Supporters say Proposition 134 brings state law into compliance with these federal Title IX guidelines, ensuring schools do not risk losing federal education funds while protecting athletic opportunities for biological females.
Opponents argue the current federal interpretation is discriminatory. They note that Colorado's existing Anti-Discrimination Act protects transgender students' right to participate in activities matching their gender identity. If passed, Proposition 134 would override those state-level protections for school sports, which opponents say harms vulnerable youth.
Go deeper, if you want
We had two AIs summarize this independently Minor differences
Both models got the same official text, the same instructions, and could not see each other's answer. Here is each one in its own words.
Claude
Every school-based team or sport, from elementary school through college, would have to be labeled male-only, female-only, or mixed, based on biological sex - defined by whether a person's reproductive system is organized around producing sperm or eggs. Students compete on the team matching their biological sex, or on a mixed team. Girls may play on a boys' team if no girls' equivalent exists. The measure does not specify how a school should verify sex; each school or district decides. Schools also could not be investigated or penalized for designating a team female-only.
Flagged: It sets a standard with no verification method, and the Blue Book says outright that it is 'unclear at this time' how the measure interacts with the Colorado Anti-Discrimination Act. Enforcement is specified only for public K-12 - there is none for private K-12, colleges, or athletic associations.
Gemini
Proposition 134 requires all school sports teams from elementary school through college to be categorized as male, female, or coed based on biological sex. Students must play on teams that match their biological sex or on coed teams, though females can play on male teams if no female team exists. It also requires schools to create policies to enforce this and prevents schools from being punished for having female-only teams.
Flagged: The measure requires schools to verify biological sex but does not provide a specific method, meaning students could face different testing rules depending on their school district.
Where they came apart
- Both independently identified the central problem the Blue Book describes: the measure mandates a standard but specifies no method of verifying sex, so each school invents its own.
- Gemini omits the two legal complications. The Blue Book says in plain terms that it is 'unclear at this time' how the measure interacts with the Colorado Anti-Discrimination Act, and that an enforcement mechanism exists only for public K-12 — none is specified for private schools, colleges, or athletic associations. Claude includes both.
- Gemini compresses to two arguments per side where the Blue Book gives distinct fairness and safety/privacy arguments for, and discrimination and belonging arguments against. Claude keeps three.
The comparison notes were written by Claude — one of the two models grading the contest — which is exactly why both summaries are printed above them in full.
The other model's take on cost and reach second opinion
Cost: It will increase legal and administrative costs for the state and colleges to update policies and handle noncompliance. Local schools will also face minimal costs to update their rules.
Who it touches: Student athletes from elementary school through college, as well as public, private, and charter schools, colleges, and athletic associations.
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Discussion
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Source: 2026 Colorado State Ballot Information Booklet (the "Blue Book"), Legislative Council of the Colorado General Assembly, Research Publication No. 842. Read the original.