I think our views overlap. During courtship is a little different. Some straight men would find dating a trans woman, especially one who still has a penis, impossible. Others would get past it if she was the right woman.

But I am saying that reproductive anatomy, and the specifics thereof, is what a healthcare worker really needs to know. "M" and "F" are shortcuts, but they don't always apply. Some men can get pregnant, not all women can. Not all cis women can get pregnant, whether because they've had their uterus and/or ovaries removed or because they had a condition that caused their ovaries or fallopian tubes not to develop. Women with AIS are cis, but don't have ovaries or a fully developed uterus.

These nuances matter in healthcare. If somebody could have an M marker but also a clearly visible note saying they have a uterus and could be pregnant, then I see that as the clearest way to make sure that the medical provider knows to, ya know, check for pregnancy, without the trans man ending up being called "Ms."

Biology is messy and complicated and human interventions such as hormone treatments and surgery make it messier.