+Sure, _in the limit of arbitrarily advanced technology_, everyone could be exactly where they wanted to be in sexpsace. Having said this, we have _not_ said all the facts relevant to decisionmaking in our world, where _we do not have arbitrarily advanced technology_. As Yudkowsky [acknowledges in the previous Tweet](https://twitter.com/ESYudkowsky/status/1067488844122021888), "Hormone therapy changes some things and leaves others constant." The existence of HRT does not take us into the Glorious Transhumanist Future where everyone is the sex they say they are.
+
+Rather, previously sexspace had two main clusters (normal females and males) plus an assortment of tiny clusters corresponding to various [disorders of sex development](https://en.wikipedia.org/wiki/Disorders_of_sex_development), and now it has two additional tiny clusters: females-on-masculinizing-HRT and males-on-feminizing-HRT. Certainly, there are situations where you would want to use "gender" categories that use the grouping {females, males-on-feminizing-HRT} and {males, females-on-masculinizing-HRT}.
+
+But the _reason_ for having sex-segregated sports leagues is because the sport-relevant multivariate trait distributions of female bodies and male bodies are quite different.
+
+[TODO: (clean up and consolidate the case here after reading the TW-in-sports articles)
+
+The "multivariate" part is important, because
+
+Different traits have different relevance to different sports; the fact that it's apples-to-oranges is _why_ women do better in ultraswimming—that competition is sampling a corner of sportspace where body fat is an advantage
+
+It's not that females and males are exactly the same except males are 10% stronger on average
+
+It really is an apples-to-oranges comparison, rather than "two populations of apples with different mean weight"
+
+https://www.lesswrong.com/posts/cu7YY7WdgJBs3DpmJ/the-univariate-fallacy
+https://www.lesswrong.com/posts/vhp2sW6iBhNJwqcwP/blood-is-thicker-than-water
+
+If you just had one integrated league, females wouldn't be competitive (in almost all sports, with some exceptions [like ultra-distance swimming](https://www.swimmingworldmagazine.com/news/why-women-have-beaten-men-in-marathon-swimming/)).
+
+]
+
+Given the empirical reality of the different multivariate trait distributions, "Who are the best athletes _among females_" is a natural question for people to be interested in, and want separate sports leagues to determine.
+
+(Similarly, when conducting [automobile races](https://en.wikipedia.org/wiki/Auto_racing), you want there to be rules enforcing that all competitors have the same type of car for some common-sense-reasonable operationalization of "the same type", because a race between a sports car and a [moped](https://en.wikipedia.org/wiki/Moped) would be mostly measuring who has the sports car, rather than who's the better racer.)
+
+Including males people in female sports leagues undermines the point of having a separate female league.