[nomadking]

Sports are separated by physicality, whether by biological sex or age. Once you have gained muscle mass(from biology or illegal steroids), you can retain it by training more. Any gain from being male or taking drugs, is still there.

Toilets and changing rooms are a bit more complicated. The underlying basis doesn't really involve biological sex or any gender ideology. The underlying basis is what you find sexually attractive, which historically has been on the simple premise of biological sex.