I don’t think it’s a concern, although I can understand why there’s a concern: TRAs are batshit, super competitive sports parents are batshit, put the two together…But my reasons are this:
• I think involvement in a social sport like swimming at a young age is likely protective for early transition, like most sports.
• I see how there is now a debate over “degree” of male puberty. Well that’s easily solved, but with the one thing everyone hates the idea of: genital inspection. A doctor would need to Tanner stage a male, coupled with records of bloods.
• but what will that show? It will show that males who are puberty blocked as part of transition have their genitals frozen at Tanner 2. Which is exactly the sort of fact TRAs want to avoid getting stuck in the public consciousness.
• Anyone who does transition fully with puberty blockers and CSH will never, ever be competitive in sport. No male who does this will be fit enough, well enough, nor good enough to compete with, let alone beat women. No female will be well enough, nor have any hope in hell of beating males.
• So the main risk will be a male who has been through male puberty, and their sporting organisations help them pretend they haven’t and lie about their pubertal staging with false records of transition. It’s not beyond the scope of Russia, or China, who have lied about gymnasts’ ages.
So the best thing overall would be sex chromosome testing and independent verification of something like CAIS.
(I still think, and have argued this here in the past, that there are unanswered questions about CAIS with small preliminary evidence showing it’s a condition over represented at the Olympics, but it can only be solved by mandatory sex chromosome testing.)