BraveSirZaphod , 9 months ago

This is true insomuch as you define sex as the 46th chromosome, but an argument can be made that that is overly simplistic. Nearly every cell in our body experiences some amount of sexual differentiation, and this is often mediated by Testosterone and Estrogen exposure. The complicating part is that trans people undergoing hormone replacement therapy do dramatically change their hormonal profile, and while some tissues are only meaningfully sensitive to sex hormones early in development (no amount of HRT is going to change your skeleton, for instance, or cause someone to grow a uterus), other tissues do remain sensitive to sex hormones and can meaningfully differentiate in adulthood causing significant medical effects. Estrogen, for instance, promotes blood clot formation, which is why (cis) women have a higher rate of them. Trans women who take estrogen, as would be expected, also have a higher rate of blood clots compared to cis men. If trans people are only changing gender, and gender is a strictly social phenomenon, we can't really explain this. Likewise, Testosterone can promote higher cholesterol levels that lead to heart attacks, which is why men have higher rates of them. Trans men taking Testosterone also experience this.

So, the fact of the matter is that trans people taking hormones go through biological changes that exactly parallel natural sexual differentiation, albeit in limited form. This has direct clinical relevance, as a trans man seeking cardiovascular medical support should not be treated the same way as a cis woman. Given this, there is a sound argument to be made that "biological sex" as defined in this way simply isn't sufficient to describe these kinds of people. At a biological level, they really do represent a kind of intermediate state in sexual differentiation, and this bears medical significance.

What it doesn't really bear, however, is social significance outside of very close intimate personal relationships. Regardless of whether you think having a strongly gendered society is a good thing or not, the fact is that we don't determine social gender through magical Chromosome-Scopes, but rather a complex mix of perceived traits, both of the body and things like voice, hair, clothing, personality, etc.