This is great news and huge thanks to the female swimmers who've spoken up to get this ruling agreed. Very very brave.
I am disappointed by the inclusion of the transition before 12 years element. I understand that it's aim is to state that's it's male puberty which confers the advantage, but it does suggest that 'transition' is a real thing and children can undergo it and then they're validly the opposite sex.
Also, I'm going to admit: I don't care much about how trans people take part in sport. It's really not top of my concerns in life.
I'm happy with just male and female categories and everyone just takes part in the category relevant to them, and meets the same rules as everyone else on drugs etc.
Job done. No need to think about anyone's identity at all.
If there are people who want special categories and races for Trans people they can get busy fund raising and organising. I wouldn't object, but I really don't care myself whether this exists or not, it is not an issue which feels important to me.
I know I'm supposed to at least pretend I care, but I don't.