I have said it before, and I will say it again. People who have TV's in their cars are not allowing their children to have some very important conversations.
Here was how my truck sounded on the way home from cubscouts:
D: When you eat food it goes down to your toes and then you poop
J (who is older and learning about organs at school): D that is not what happens...first you swallow and your food goes here (pointing) in your stomach...then it goes in the really big long pink thing that looks like a snake and that takes out the good stuff and then it comes out as poop.
D: Is it really big?
D: Then were is the baby?
J: (holding his hands up like he is taking control): I know where babies come from
Nanna (inside her head): OMG think think think!!
J: Inside a girl there is this tiny little thing with a line across it. Every time she eats food some of the food feeds that and it turns into a baby. Then with more food it gets bigger and bigger until it finally just comes out.
D: (puzzled shocked expression) Nanna did you have a baby in your tummy?
Nanna: (releaved) yes two
D: where are your babies?
J: (condesending older brother voice) D it is mommy and uncle tom tom
D to Nanna: You laid them!?
J: D! we don't lay babies....we're amphibians!