It's not incest, it's masturbation! XD Or maybe it's narcisistic like: A "If I ever met a someone that was me but girl version (either natural coincidence, cloning or parallel universe)i'd f*** myself. I mean her" kinda thing.
In THE MAN WHO FOLDED HIMSELF, the title character did just that. And got her pregnant. Producing the baby boy who would one day become him/the baby girl who would one day become her. In the Brit TV series MISFITS, one character with the power to switch between male and female forms got himself pregnant.