A wealthy old man marries a young woman... Before long they are in the hospital delivering their first baby. ""Congratulations its a healthy boy,"" the doctor says to the elderly man. ""How did you do it at your age?"" ""Well Doc, I just have a great running engine."" the man replies. A few years later the man and his wife return to have their second baby. Again the doctor congratulates the old man, and asks again, ""How do you have the energy keep having these children?"" Again the man says, ""I told you Doc. I have a great running engine!"" The man and his wife return again a few years later for their third baby. Troubled, the doctor says to the man, ""I'm very sorry, but your engine appears to be burning oil, because this baby came out black.""