If you believe that, you need to look at the latest research.Hashi Lebwohl wrote: rather, the problem exists inside your mind--somewhere along the way, someone or something made you feel uncomfortable with yourself and deciding that you are trans is the expression of that discomfort. In other words, if you don't like yourself as a male you aren't going to fundamentally like yourself as a female, either--you are still you inside your mind.
I also find it a little odd that you would think that a persons identity is really determined by visible bodily characteristics, and not their minds [completely ignoring the problem that the brain you have is ALSO a bodily thing.]
There simply isn't a hard dichotomy, any set line...just varying commonality/prevalence.
You're worried that they might just lie, and we have to trust them...
I have to tell you that a manly man [or teen] willing to try to fool everyone...friends, family, society...into thinking he's got a gender conflict, and put up with all the problems that causes, in order to see naked girls [and MOST of the time, he won't be seeing any nakedness...he'll just find himself forced to confront the fact that girls pee, poop, and fart, too...and it's just as messy and stinky for them as it is for boys/men] has WAY worse mental problems than someone who really does have a conflict.
[[none of the other pretending schemes/patterns/dangers make any more sense, though the specifics may vary]].
If one is worried about sexual violations and vulnerabilities, one should move the transgender stranger school/public worry to the bottom of the anxiety page---and move to the top and bold-face born gender relatives and friends at home/private.