This bill would change Title IX — the federal law that bans sex discrimination at schools and colleges that get federal funding — by saying schools violate that law if they let someone who was born male compete on a girls' or women's sports team. Sex would be defined by a person's biology and genetics at birth, not by gender identity, so this specifically affects transgender girls and women trying to play on female sports teams from K-12 through college. Male athletes could still practice or train alongside a girls'/women's team, as long as doing so didn't take away playing time or opportunities from the female athletes. The bill also directs the Government Accountability Office, a federal agency that investigates and reports on government and policy issues, to study and report on what girls and women might lose — competitively and otherwise — when male athletes participate in their sports.