An anatomy lesson as given by my 4 year old!

Cole: Mom, do you still have milk in your boobs?
Me: No ,not anymore.
Cole: Because you don't have a baby?
Me: That's right, cause mommy doesn't have anymore babies.
Cole: Now you just have water filling them up!
Me: Well... no... there's no water in there.
Cole: Then why are they like that?
Me: Well, that's just the way big girl's boobs are so that when they have babies they can have milk.
Cole: Only girls have boobs, I'm a boy and I have two nickels right here up on my chest!

What will he ask next!