// *There are, in fact, "XX men and XY women", in the sense that for whatever reason, even at birth the genetically-determined sex doesn't match the outward appearance. This is separate from, but of course related to, transgender, because it shows that XX/XY is very much not "end of". //
There are not. In any sense. XX is always female. XY is always male. One's biological sex cannot change. Gender is a social construct. How does a male 'know' they 'feel like a woman'? They cannot know what a woman feels like.
Self ID is a nonsense. It's how this male rapist got into a women's prison and sexually assaulted vulnerable women there.
https://www.theguardian.com/uk-news/2018/oct/11/transgender-prisoner-who-sexually-assaulted-inmates-jailed-for-life
I don't care if anyone dresses up however they like. I don't care if goes about calling themselves a different gender. But I don't want a bloke in a frock perving around in my changing rooms or bogs.