Grow up to be a Grandpa?

Over dinner the other night the question was posed by one of our kids,

"But how do you really know if a baby is a boy or a girl?"

Eliza chimed in first thing, "It's easy," she said, "If you grow up to be a grandpa, then, well, you are a boy!"

So if you can wait 60 years or so, you should be able to determine your gender :)