Um, I hope no-one really thinks we'd actually discuss things like that with her. We are open and honest, (and I tend to be too scientific to where her eyes glaze over), but we're certainly age-appropriate as far as sex information.

Bob: Mama, where did I come from?
Me: Well, Sweetie, when someone wants a baby, the sperm and the egg...blah blha blah...and the babies grow in the woman's uterus, and then they come out of her vagina, and that's how you were born.
Bob: Mama! What *city* was I born in?

Heh.