FYI: on November 6, 2023, a US federal District Court judge dismissed a lawsuit by and on behalf of a trans-identified male HS student that challenged the legality of Florida's "Fairness in Women's Sports Act."
That law, which went into effect in July 2021, bars all males regardless of their gender identities and expression from girls' and women's school and school-affiliated sports in the state.
The judge ruled that it's lawful and legitimate under the US constitution and Title IX for governments to have a law prohibiting all males from female school sports.
The plaintiff’s lawsuit alleged that by not allowing the male trans-identified student to participate in girls' school sports, the Florida law is singling out the student for unlawful and unfair discrimination based on the student's sex and gender identity. But the judge ruled that the law treats all male students of all gender identities - and no gender identities - in the exact same way and thus the student is getting equal and fair treatment under the law.
The judge said it's justifiable for legislatures to bar all males regardless of how they “identify” from female sports because it's well established that the government has a legitimate interest in providing and insuring equal opportunity, fairness and safety in sports and education for female people in the USA.
However, the judge did give the plaintiff leave to amend the complaint and continue to challenge Florida's Fairness in Women's Sports Act on the grounds that it might unlawfully discriminate against the plaintiff based on sex in one respect.
This is because Florida's law treats female trans-identified students more favorably than male ones by giving them more options for doing school sports. Whereas male students with trans identities are all barred from girls' and women's school sports across the board without exception, female students with trans identities who aren't taking exogenous testosterone can play girls'/women's sports - and/or they can play boys'/men's sports (if they're good enough to make male teams, and them playing with mostly males doesn't create any safety issues, that is).