That's an interesting question. I don't know. But, there are people today who have elective cosmetic surgery again and again and again because they're never quite satisfied with the way they look. IMHO, "reassignment" is very much like other elective cosmetic surgeries. They're all about outward appearances, and some people will never be happy.
It's sad. But, because they refused to play along and instead looked for help for their son in other ways, this teen's parents were good parents, even though he himself didn't understand that.
I agree. Those who “transition” seem more trapped than the usual by their idea of who men and women are and what men and women do, rather than that men and women are free to have their own interests regardless of their sex. Thus, they want to become their clownish idea of what the opposite sex is or does by changing their own sex.