Puberty.

Setting: Emily and I are in the bathroom. I am peeing, the water is running and she is taking her shirt off. (She's just recently figured out a way to get her shirt off by herself. She pulls the head hole over and behind her head, and then pulls it off her arms. Which means there's a point when the shirt is behind her neck and her arms are still in the holes, kind of as if she were wearing a shawl.)

Emmy: Momma, look!

Me: What baby?

Emmy: I have nipples.

Me: ... Most people do.

Emmy: Aren't they pretty?

Me: Emmy, you're beautiful.

Emmy: Um, yeah. I know. I mean thank you! Someday? Mommy, I'll have boobies like you. And they'll be biiiig and they'll bounce when I jump!

Me, as Emmy is jumping up and down while trying to look at her chest: Um, Emmy, it's not nice to talk about boobies.

Emmy: Ok. But someday I'll have 'em. When I'm older. Cuz now I'm a kid. So I just have nipples.

At least she knows her body parts, right?