So everyone was originally female. That's a basic fact. The ovaries, descend down and become testicle. This is why when you get kicked in the balls, you feel it in your stomach area. It's where the ovaries normally set. The clirotis extends out and becomes a penis. The g spot doesn't really move, it just stays there and the only way to access it is through the rear exit.

Trust me, I'm a random internet stranger with no background (formal or informal) in Physiology or Biology or anything related to that in any way.