There was a story on the BBC half an hour ago. Apparently a little boy went up to his Mummy and said "Where did I come from?". Mummy gulped, spoke to Daddy and they decided that this was the time to let him have the full facts. So they sat him down and gave him a half hour sex chat with no detail spared.
After they had finished they asked him if he had any questions. "Well, that's all very interesting," he replied, "but what I really wondered about was this new boy in my class. You see he says he's from Sheffield"