Halloween postscript: blowing the minds of the very young

We had a Halloween party at work yesterday afternoon, with at least 90% costume participation, to which people brought their children. One little girl of about seven or eight looked at me gravely and said, "You're a boy."
"I used to be," I said.
The little girl stared wide-eyed.
"Seriously. Not anymore."
The little girl wandered off, maybe to ponder that, maybe to freak out a little.