The alternative would be to remove women and gay legal protections in law.
And in effect create a hierarchy in which some citizens get rights and control over others based on self identification.
This is why it would never get through the ECtHR: there is an absolute inability to get the TRA head around the idea that they wouldn't be the sole and only considered group, and given primacy over all others.
Or that a man desperate to get in amongst non consenting undressing women perhaps hasn't quite understood the idea of 'rights' and how they work.