Doctor gives an eighty year old man a jar to give a sperm sample. A week later the old man returns to his surgery and hands the jar to the nurse. "Why is there no sperm in this jar?" the nurse says.. "Well" says the old man "first I used my right hand, then my left. Then my wife tried with both hands, then with her teeth in, then with her teeth out! We even got Ethel from next door to have a go and still the damned lid wouldn't come off