A couple went to a doctor because the man was feeling down, tired all the time. The doctor said I will give a shot of vitamins, a prescription for some pep pills from the drugstore, and an empty jar for checking your sperm count - bring it back in next week so I can check it. When the guy came back to the doctor, the doctor said "Why, this jar is empty, I told you I needed to do a sperm count." The guy said, "I tried with my left hand, I tried with my right hand, my wife tried with her left hand and she also tried with her right hand, she even tried with her teeth.
We could not get that jar open!"