The U.S. Supreme Court on June 30 ruled that states can bar men from competing in women’s sporting leagues, dealing a blow to LGBT activists who have advocated for allowing men who “identify” as women to join female teams.

The court ruled in a consolidated set of cases out of Idaho and West Virginia that federal Title IX rules permit schools to “provide separate women’s and men’s sports teams defined by biological sex,” meaning schools can prohibit men from playing on women’s teams even if those men believe they are women.

The court had taken up the issue in July 2025 when it agreed to hear the two cases, which arose after the two states moved to block males from playing on female sports teams. 

Both cases arose from lawsuits brought by, or on behalf of, young men who identify as female and who sued against the states’ respective bans on males competing in females’ sports.

In the June 30 ruling, the court rejected arguments from the plaintiffs that Title IX requires schools to let males play in women’s leagues. The court said “safety and competitive fairness” are “important interests” for equal protection concerns, and sex-separated teams are “substantially related” to furthering those interests. 

Schools “may determine eligibility for women’s and girls’ sports based on biological sex,” the court said. 

The ruling was divided largely 6-3, though three of the court’s four female justices — Sonia Sotomayor, Elena Kagan, and Ketanji Brown Jackson — filed partial concurring opinions. 

Sotomayor wrote that though she was sympathetic to concerns of fairness in women’s sports, the ruling “inflicts a hardship” on athletes who identify as the opposite sex. 

She argued that the U.S. Constitution requires a “fair and full opportunity” for the plaintiffs to litigate the dispute. However, she said the Supreme Court’s decision treats the issue as a “winner-takes-all” situation and makes it too easy for sex-based rules to be upheld without enough careful review.

Jackson, meanwhile, argued that definitions of “sex” in Title IX rules includes the concept of “gender identity.” A law banning male participation in female sports “might well run afoul” of those regulations, she said. 

In September 2025, Lindsay Hecox — the plaintiff in the Idaho case — asked the Supreme Court to dismiss the challenge to that state’s law. Idaho moved to oppose the dismissal; a U.S. district judge ultimately ruled against the request, claiming that Hecox was attempting to “avoid Supreme Court review.”

The debate around transgender participation in opposite-sex sporting leagues has exploded in recent years, with LGBT advocates arguing that athletes should be permitted to compete on sports teams of the opposite sex and critics arguing that female athletes should not be forced to compete against males. 

The International Olympic Committee in March announced a new policy under which men who believe themselves to be women will be forbidden from competing in the women’s category.

In 2025, meanwhile, the NCAA announced a ban on men competing in its women’s categories, though the league issued the decision only in response to an executive order from President Donald Trump threatening federal funding loss for schools and universities that fail to divide sporting leagues by biological sex.