I almost agree with all you said with one big exception.

Being transgender is not a choice, deciding to transition like Bruce Jenner did is a choice... taking steps to become physically what someone feels internally is, but it's two different things.

Try to imagine for a minute that all your thoughts, your internal voice, what you like, dislike, the way you feel not the way you look don't match up to the body you were born into. You are Opi through and through, but you look in the mirror and you have boobs, a feminine face, you are expected to think, act and present yourself as a woman, but you feel like a man.

I'm not trying to be funny here and I'm probably not explaining my point all that well, but your own internal self identity is not a choice, transitioning is.

Yes, we are all born with male or female genitalia, but gender identity is formed in the brain.