@donquixotedelamancha They have changed their legal sex though. Not their biological sex, but their legal sex.
We don't have legal genders.
Obviously the whole thing is a mess. I think probably we need a system where everyone has a legal sex (which cannot be changed) and people can have an optional legal gender if they wish.
It would massively help in a healthcare context.
And then for things like sports and prisons we could say legal sex only is what counts. And for things like rape therapy groups have some for legal sex alone and some for gender.
The blurring of language around sex and gender is what has got us into this mess.