Gender testing for women Olympic athletes, eh?
Basically, they want to make sure none of them are really men, and they do this by testing chromosomes (because that's the only place that gender is located, right? Right. No genderqueer consideration here!). Of course, some women have other chromosomal abnormalities, so if that comes up there's a physical exam (which makes little sense to me--why the chromosomes if we can just check up your skirt?), which is gross and invasive, and them some women are STILL barred from competing.
As far as I can tell, they don't test men this way. Because, of course, the assumption is that women couldn't possibly be that good at sports, so some of them are probably men in shorter shorts.