Yeah for sure, I think that's one aspect - you can't just say anyone above this level is a man, anyone under is a woman. There's also the observation that for T levels as well as a whole bunch of other metrics like height/weight/etc, the AVERAGE difference between a cis man and a cis woman is way smaller than the spread of differences within the gender. I also thought the point about endogenous T levels NOT being correlated to athletic performance was super interesting - it seems like your body's baseline T level is just a 0 point, and if you do something to increase from your baseline, athletic performance improves, but there are still cis men with T levels 80x lower than other cis men but who are still competing at an elite level, because that 0 point is just different but it doesn't mean that one has an advantage over the other. So all this talk about gendering people based on T level is just nonsense based on a faulty premise that a higher baseline is an inherent advantage, which it isn't.

Hope I didn’t come across as contradicting this stance in any way - the author of this tweet thread is one of the most famous trans female athletes and has obviously done a ton of work for trans women’s right to compete in sports. I thought it was pretty interesting! But I understand discussions about trans people in sports are fraught and even in seemingly supportive spaces it tends to bring so-called “gender essentialists.” My hope was that some of the points in this thread would attack such arguments on a VERY fundamental level.