"it sounds like the same (sadly "standard") fallacious lumping of trans* women (who are women) in with cisgender men"

Naw. It simply parses gender from sex. A MD would be foolish if he assumed that the Trans Woman is a Woman biologically and that her biochemistry and physiology should never take into account the fact that she was born male. Similarly, if you are addressing her upbringing or biology pre-transition, you need to avoid conflating her gender and her sex.

Sure, the distinction may confound those who think stereotypically. ( But then again so does hair-length. ) But pretending that every woman who deserves to be treated as such societally should also be treated as such medically, regardless of how they became female, is a drastic oversimplification.

Dante