I'm not quite sure how to apply it to this conversation, but I was thinking about weight classes in the combat sports and whether they'd be of any use in other individual sports, or even in team sports. We do separate children by age, and there are leagues for people over a certain age. In combat sports, we separate athletes by size, because size is such an advantage and we want the smaller athletes to be able to compete. We use weight, or mass, rather than height. I'm not sure there's a reason not to use height, especially in a sport where height might matter. Would it make any sense to group swimmers by height, for example?
I'm also thinking of the high school girls (I think there were two) who won state wrestling championships in the last few years, competing against boys. iirc, the girls were allowed to compete with the boys because there wasn't an organized girls' competition. In wrestling, your weight class is important, because size is a natural advantage that we choose to account for artificially in order to allow smaller people to compete*. So these two girls were allowed to compete with boys and they won. I don't know how many girls overall were competing against the boys, but it couldn't have been many, because if there had been a lot they would have just created a girls bracket. So it's hard to say that these two happen to be among a tiny minority of high school girls who'd be capable of competing against boys. Even moreso, these two made the news because they didn't just compete against the boys, they won their state championships. So maybe there are lots of girls who'd be capable of competing with boys; we can't really know because we haven't really let them try.
I dunno, just thinking out loud.
* Although in some sports, like jiu-jitsu, open-weight competitions still exist, and the smaller athletes do sometimes win. I'm thinking of 5'4" Mackenzie Dern vs. 6'2" Gabrielle Garcia. Of course this instance of an athlete with such a dramatic size disadvantage winning sticks in the mind precisely because it's so unusual, but like I say, open-weight events do still exist, and not just as exhibitions.