Let's face it, there's a point in every human beings life when they: (My answer) Position themselves just so upon a mirror, so that they can check out their own asshole.
...when they have a daughter, but raise her to think she's a boy. Then, once in awhile walk in while she's peeing or is taking a bath and freak out, screaming "Where the fuck is your PENIS?! WHAT DID YOU DO!?"