Even if this supposed difference in desires to have a transplant exists to some statistically significant extent (I’ll leave it to our informed transfolk here to confirm or deny that), I suspect it could have a simple explanation.
Women’s genitalia are mostly internal.
Men’s genitalia are mostly external.
We tend not to think much of accepting the transplants of internal organs (think heart, liver etc.) from the bodies of other people. After all, these are organs we don’t see on a daily basis — we know they’re there, but there’s a bit of a distance there in that it’s a somewhat abstract knowledge.
Men’s genitals, on the other hand, are something that (cis) men see and interact with (not in that way… mostly) on a daily basis. This might make their genitals more… personalized, if that makes sense? Thus trans men might not be quite as eager to have genitals that used to belong to someone else, as you’d kind of be very aware of that fact every time you go to the toilet (or have sex, or masturbate).
Trans women might be a bit more fortunate there in this hypothetical scenario, as they wouldn’t have nearly as much of a direct visual and tactile link with their uterus at least.
Am I making any sense?
Also, when it comes to trans women, they might value being able to give birth more than trans men would value having, say, functioning testicles.
Reproductively speaking, whereas for men it’s a difference between, say, your partner being impregnated by you or by a sperm donor, for trans women it would be the difference between adopting or seeing a partner going through pregnancy… and being pregnant yourself, with the whole physical and emotional experience that entails. And that seems like quite a big difference.
In short, the OPs’ comparison is flawed, because the male and female reproductive experiences are vastly different. Thus, it’s sort of an ‘apples and oranges’ scenario.