I think one of the reasons why I'm so angry about this is that I had to write an essay for a college biology class about intersex athletes, about ten years ago. I wasn't interested in gender at all back then, it wasn't a topic I have, nor had, any interest in, and after ten years of quietly not caring about what I had learned after earning my A-, it's suddenly the hottest shit on the block.
Here's the upshot: the standards by which we judge transgender athletes after hormonal intervention, were developed in the first place for intersex athletes. It turned out that you couldn't predict a person's athletic performance that readily just based on how things looked in their pants so just a secondary sex characteristic check wasn't enough. They decided on lines based on hormonal levels to define what it meant to compete as "male" or "female." And these days, with these guidelines updated for transgender athletes, the line of separation is decided sport by sport.
(This whole business about dickering over hormone levels reminds me of nothing so much as the stereotype of parents looking at their active male infants and proudly saying that the boy is surging with testosterone. He is not. That is a baby and yes, he probably has an "outie," but hormonally it's more or less indistinguishable from a girl. You are looking at literally exactly the same behavior between male and female infants and saying that it's because of "hormonal manliness" in the one but not the other.
But I digressed...)
It also turned out that Olympic athletes overwhelmingly were blessed with modifications of specific genes, male AND female, one of which improved muscle definition and tone from a very young age (visible on photographs of toddlers) and another of which improved blood oxygenation.
But not all gold medalists had these two biological markers, which was also curious. The IOC considered banning athletes with those genetic markers and other "supergenes" but haven't so far.
I get angry about this topic because every single last rule which is intended to remove transgender athletes from competition ALSO removes "legitimate" female athletes from competition, whether it's about height, hormones, suspicious secondary sex characteristics, musculature, facial and body hair, or what have you. Recently the primary attacks have been on African women, but before, there were plenty of prominent cases with white cisgender women.
If you want to ban transgender athletes, fine. How do you find them? No, just not the obvious ones. How do you know you have found ALL of them? How do you make sure that you remove ONLY transgender athletes and zero athletes who have, as far as the paperwork has always shown, been cisgender females?
There are only two options on the average birth certificate: Male, and Female. Lots of intersex people have been lumped into the umbrellas of Male, and Female. They have what you might call "visibly mixed" characteristics from the day of their birth, but their socialization has historically only been one of two options: Male, or Female. And they have historically had the right to participate with their assigned sex, despite having blended physical qualities of Male and Female from day zero--including hormone makeups that don't suit their gendered socialization, in many cases.
My point is not "it is unfair that intersex people have better treatment than transgender people." Coercively assigning intersex people into particular roles, often through the intervention of surgery, is not really helpful, and can cause both gender dysphoria and a lot of physical pain.
(For those who want to complain about surgeons cutting into healthy organs in late adolescents or adults: first let them stop cutting infants. I'll wait.)
My point IS, however, that the more people circle the wagons on "protecting girls' sports," the more you are going to find cisgender people with intersex characteristics who are negatively affected by this, and the more you are going to find that the ones who the rules claim to protect are a scrutinized and over-scrutinized class. The paragons of cisgender womanhood often have their own embarrassing little secrets. They don't actually need to be revealed just to make sure you weed out every transgender person. Create a line at which transgender people can participate and if transgender people start to win everything, then you can change the rules ... IF that happens.
And finally, I'm angry about all of this because it sounds like the bar for success is that an exceptional transgender woman must never appear, and perhaps worse, that an exceptional cisgender woman must never appear. Anyone who ever approaches a male level of excellence and breaks all barriers must have been cheating, and when she appears, the rules of the game must change to eliminate her from the field.