Probably true as a practical matter in dealing with a specific RL person.
I’m discussing how people categorize things in abstract. This is then reflected in - among other things - the way they say things like “made into a woman” or “used to be a man” (which triggered the discussion here).
This is sort of a hijack, but it’s something I’ve always wanted to know. What effect does male to female transgender conversion have on male pattern baldness that has already occurred before the process is initiated?
Apparently there is no such thing as male-to-female transgender conversion, therefore there cannot be any such thing as male pattern baldness that has already occurred. So your question is meaningless.
It is not a matter of evidence or fact at all. It is a matter of social and ethical convention. You may well be able to make a very good case that your preferred social convention (which amounts, IIUC, to treating trans people as members of the sex that they feel they ought to be, rather than the one that their body at birth looked like) is preferable in terms of minimizing conflict and maximizing the general happiness, or whatever, but that does turn the issue into a matter of objective scientific fact.
As for the question of whether transwomen or cismen are more likely to get prostate cancer, I am pretty confident that that is something on which there may be theories, but, as yet, very little statistically meaningful evidence.
(By the way, I believe the official term is “male to female gender (or sex) reassignment”. There is nothing incorrect, AFAIK, in saying that the original body of a transwoman was biologically or anatomically male; what is objected to is the (frequently encountered) claim that the transwoman herself “wasn’t a woman” until she physically transitioned.)
AFAIK, hormone replacement therapy in transitioning to a female body may prevent male-pattern baldness in some transwomen but it doesn’t automatically reverse the effects of hair loss that happened pre-transition. Women who’ve experienced hair loss may take androgen blockers and use minoxidil, or get hair transplants or wigs.
I presume you mean “does not turn the issue into a matter of objective scientific fact”, but I think the point is that there isn’t any “objectively scientifically factual” way to define what it means “to be a woman” or “to be a man”.
We can say for the vast majority of people “This person’s body at birth had a penis and testes rather than a vagina and uterus” or vice versa, and that’s pretty objectively scientifically factual. (Not entirely, of course, because some people who are anatomically intersex at birth can’t be described with that simple binary opposition.)
But using “man” to mean just “this person’s body at birth had a penis” and “woman” to mean just “this person’s body at birth had a vagina” fails to take into account the lived experience of identifying as a man or woman, which may contradict the anatomical definition. It’s sort of like identifying people by their Social Security number instead of their name: it may be precise and unambiguous but it isn’t what we mean when we talk about who they are.