Coming from a place of curiosity not knowledge with this. Is it not true that strength roughly matches testosterone levels and that is bimodal in the population? Could what we call women’s sports today not be defined on that axis instead?
Some sports actually do test for testosterone in order to determine eligibility (I believe volleyball?)
Also, interestingly enough, people that do estrogen injections end up with lower testosterone production. Estrogen also tends to (but not always!) block the effects of testosterone.
Hormones are weird and how individuals react to them is all over the board.
And example of that craziness is what the article refers to. People with Y chromosomes and uteruses. It's caused (AFAIK) because the fetus didn't respond to the hormones which cause the gonads to turn into male reproductive organs.
In theory.
The problem is that for example in women boxing these people are overrepresented. This indicates that testosterone is possibly not the only answer, and we don’t know the full picture AFAIK. But of course it’s also possible that simply Y chromosome causes changes in behavior and not physical performance, and it’s more likely that they like boxing more. We don’t know.
The current best proven differentiator AFAIK is testosterone level and whether their body can process that.