The International Olympic Committee, for example, has a framework for precisely this (you can read it here, it's pretty easy going: https://stillmed.olympics.com/media/Documents/News/2021/11/I... ) and I think it demonstrates really well that they've put a good amount of thought into being fair.
I think you'd have a hard time saying that the IOC framework is discrimination.
No, by their sex - just like everyone else.
There is a blanket ban on men participating in women’s sports - is that discrimination ?
No, it's not.
> Is-it discrimination to forbid trans-women to participate in the same sports category as bio-women?
It is absolutely discrimination to discriminate between cisgender and transgender competitors.
Whether it is acceptable discrimination is a value question, whether it is legal or permissible discrimination depends on the relevant law and rule framework, but it is unmistakably discrimination.
Chuck "discriminate" into Google and you'll get two definitions:
> 1. recognize a distinction; differentiate.
> 2. make an unjust or prejudicial distinction in the treatment of different categories of people.
I was referring to the latter use.