"Sperm Count" joke

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 reappears at the doctor's office and gives him
the jar, which is as clean and empty as on the previous day. The doctor asks
what happened, and the man explains, "Well, doc, it's like this. First I tried
with my right hand, but nothing. Then I tried with my left hand, but nothing.
Then I asked my wife for help. She tried with her right hand, but nothing. Then
her left, but nothing. She even tried with her mouth, first with the teeth in,
then with the teeth out, and still nothing. Hell, 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 damn
jar open!"