What's the point of gender reassignment surgery which doesn't change a person's chromosomes?

This can include the SRY gene being defective, being blocked by other mutations, being on the X chromosome instead of the Y, or missing altogether.

It doesn’t have to change chromosomes, because chromosomes do not determine sex.

The single thing that does determine sex is the SRY gene. Its discovery in 1990 changed everything science thought it knew about sex in placental mammals.

Trump is shot, tackled by SS agents, yet then stands, defiant, with fist high, and 52 hours later, walks into the Republican Convention to thunderous applause. Is there anything that can stop this man, who loves his country? Does he get your vote?

In other words, these different levels don’t always sync-up. It is possible for your brain, your body, and your genetics to have different biological sexes.

Corollary: sex and gender in humans is actually floridly-complex and occasionally very messy.

All of these variations have an effect on the person’s neuropsychology and thus their experience of their sex & gender.

If you cloned 12 Michael Jordan's and 12 LeBron James' and had Team Jordan vs. James, which team would win the most games?

So what happens inside “gender-affirming care” depends upon the patient’s lived experience. However, it’s been demonstrated conclusively by a century of psychiatry trying to change transgender patients’ gender identity to match their physical anatomy does not work and in most cases only worsens their mental health, especially in minors.

It’s usually found at the tip of the Y chromosome (which is why we thought sex was in chromosomes), but there are a number of variations that will change a person’s anatomical sex, neurological sex, chromosomal sex, and genetic sex.