The U.S. Supreme Court on Tuesday upheld state laws banning transgender girls and women from competing on female sports teams.

The conservative-majority court ruled that such bans in West Virginia and Idaho do not violate the Constitution or Title IX, the federal law that prohibits sex discrimination in education.

Writing for the majority, Justice Brett Kavanaugh said schools can determine eligibility for women’s and girls’ sports teams “based on biological sex.”

“Separate sports teams for biological males and biological females are reasonable,” he wrote.

Twenty-seven states have adopted similar bans on female transgender athletes, arguing they are intended to ensure fairness and address safety concerns for non-transgender girls and women.

There are no definitive statistics about how many students nationwide are affected by such bans, per USA Today.

The Williams Institute at the UCLA School of Law estimates that as many as 122,000 transgender youth could be participating in high school-level team sports.

NCAA president Charlie Baker told a Senate panel in 2024 that he was aware of fewer than 10 transgender athletes among the more than half a million student-athletes on college teams.

–Field Level Media