then if he ever has sex with that guy(forgot him name like take-something (to lazy to go look)) he could get pregnant idk usually in genderbender stories like these they show like a 10 yr later time skip and they have kids but doesnt show the process of then getting their periods some shows but not much but unless the author wants to make it more ecchi than it already is i dont think hes going to add it in :P ლ(´ڡ`ლ)
If he is a girl, then will he is period one day?