A 75 year old man went to his doctor's office to get a sperm count. The doctor gave the man a jar and said, "Take this jar home and bring me back a sample tomorrow."
The next day the 75 year old man reappeared at the doctor's office and gave him the jar, which was as clean and empty as on the previous day.
The doctor asked, "What happened, didn't I ask you to bring me back a sperm sample?"
The man went on to explain, "Well doc, it's like this: first I tried with my right hand, but nothing. Then I tried with my left hand, but still nothing. Then I asked my wife for help. She tried with her right hand, but nothing. Then she tried her left hand, still nothing. She even tried with her mouth, first with the teeth in, then with the teeth out, and still nothing. We even called up the lady next door and she tried with both hands and her mouth too, but nothing."
The doctor was shocked!
"You asked your neighbor?"
The old man replied, "Yep, but no matter what we tried we couldn't get the damned jar open."