[user104658]

The "trans men (biological women) shouldn't use male toilets" conundrum is a major, major stumbling block I cannot even fathom what the solution there is going to be. Literally any bloke could walk into a women's changing room claiming that they are a trans man and I can't see how anyone could prove one way or the other without peeking their genitals.

Being blunt; more often than not, you can tell when a trans woman is trans. People are polite and claim otherwise but most are not entirely "passing".

But testosterone therapies have a HUGE effect on biological women and trans men can easily look 100% male, if often on the short side, but we can't go assuming that all short kings are actually biologically female.

I dunno how that's going to be solved.

Honestly I think the simplest safeguarding solution would be to say that biological men can't use women's spaces, but biological women can use men's spaces if they choose to. Trans men should, if they choose to, still use men's toilets.

That would be a nightmare (or basically impossible) to write into any coherent law though.