The Difference Between Boys and Girls

I am in the bathroom and of course my four year old son comes walking in.  He smiles and then looks puzzled. I say, "Whats the matter?"  He says, " Mom why do you pee out your butt? I pee like this (he demonstrates standing up pushes his pelvis foward)." I say, " I have an inny and you have and outy" . Mine is called a Vagina and yours is called a Penis. He went into the kitchen and told his sister and father the news. He said I have ENIS and and mom has a Vageena!  Sigh....