I think it's his totally undeserved confidence in saying "that medical procedure is really under researched even in cis women". I mean we're talking about a supposed transplant of the female reproductive system here, something that's obviously fiction and really should not concern men at all. And he's upset that he's unable to have one, and I can only imagine jealous of every woman he walks by on the street because of their ability to bear children. It reminds me of how troons argue getting their dicks cut off should be considered a life saving operation and prioritized among emergency heart transplants.