Why do males have nipples? The purpose of the mamalian nipple is to suckle young, but in no species does the male do that. In no species is a male able to do that. So why do males have them? It's a valid question.
How we do it is a choice -- and emotional as well as mental health play a part in that.
So... what's your point?
My point on the other issue is -- they are not born that way. It is not biology. It is not science. It is not equal to heterosexuality. No one is physically made to have intercourse with a same sex partner. No part of their biological make up supports that theory. Desire doesn't make it natural.