A 75-year-old man went to his doctor to get a sperm count.
The doctor gave the man a jar and said, "Take this jar home and bring me back a semen sample tomorrow".
 
The next day, the 75-year-old man returned to 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, and the man explained, "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, then her left, still nothing. She even tried with her mouth, first with the teeth in, then with her teeth out, and still nothing. We even called up Arlene, the lady next door, and she tried too, first with both hands, then an armpit, and she even  tried squeez'n it between her knees, but still nothing".

 

The doctor was shocked!"  You even asked your neighbor?"

The old man replied, "Yep, but no matter what all three of us tried, with our arthritis, we still couldn't get the jar opened !"