o-o Wow. I didn't know they had to. How.... sad. sweatdrop
now, I know my little brother knew more about the female anatomy by the time he was 4 than I did by the time I was 13- and that was at the same point in time. It's like my parents gave him the talks, and then me.
He was 4, and turned to my best friend, looked her up and down, and said "nice rack. And them are childbirthing hips" Mom turned soooo red.