Little Tommy asked his father, "Daddy, how were people born?"
His father tells him, "Adam and Eve made babies, then their babies became adults and made babies, and so on until Mommy gave birth to you."
Tommy then went to his mother and asked her the same question. She told him, "Well, at one time we were very stupid cavemen and cavewomen. We were all hairy and ugly, and just sat around grunting and barking and clubbing each other. Back then, we just weren't very smart. Then very slowly, we evolved to become like we are now."
Tommy ran back to his father and said, "You lied to me!"
His father replied, "No, your mom was talking about her side of the family."