This is exactly equal to the treatment of Caster Semenya, except this time it's Lia Thomas.

There's another issue, too.

In order to stay recognized by FINA, all national bodies now have to collect genetic information from their athletes.

First of all, there has been a move away from this kind of sex testing. FINA thinks they can get away with it by also requiring *male* athletes to test.

However, by forcing cis women who happen to have a Y chromosome to compete in men's or open categories, there's a potential legal case for genetic discrimination. And the only defense against that would either be: 1. Having a Y Chromosome Makes You A Man And Gives You A Competitive Advantage! This is, of course, BS. A Y chromosome with a missing SRY gene does nothing to you or 2. Men don't actually have a competitive advantage against women. Uh, in that case, there's...ya know, no reason to exclude trans women. (I honestly feel that all else being equal cis men do have a bit of an advantage in swimming mostly because of the greater height and thus wingspan they have, but I think that once somebody's been on hormones for a while they aren't going to be competitive in the men's division).

I suspect FINA will be hoisted on that petard. Hope so, anyway, because this has not been thought through remotely.

Another issue is that in the EU genetic data is considered "sensitive" as is "health-related data." That brings in an entire bunch of GDPR-related annoyances.

Also, I think there's a better way than testosterone levels to measure when a trans woman should switch to women's competition: Her performance compared to her performance as a man. When there's a notable drop...I don't know how to make that work practically, but it's something to consider.