**Proposition 135**, a citizen-initiated statute on Colorado’s November 3, 2026 ballot, would prohibit healthcare professionals from performing surgeries on minors to alter biological sex characteristics and bar state, federal, Medicaid, or insurance funding for such procedures. It qualified in March 2026 after Protect Kids Colorado submitted nearly 165,000 signatures, exceeding the roughly 124,000–125,000 valid signatures required. The measure joins a companion initiative on school and college sports participation based on biological sex, with both backed by the same sponsors amid national debates over age limits for medical interventions. Similar restrictions have passed in 25 states, while Colorado previously enacted laws protecting access to gender-affirming care. Traders’ 66.5% implied probability for passage reflects the measure’s ballot qualification, signature momentum, and voter patterns on comparable policies elsewhere, though final outcomes depend on turnout and campaign spending in the remaining weeks.