The doctor handed his 75-year-old patient a jar and ordered him to bring back a sample so he could do a sperm count. The next day old man returned to the doctor with an empty jar.
"What's this?" the doctor asked.
"Well, doc, it's like this: First I tried with my right hand-but nothing. Then I tried with my left hand-still nothing. Then I asked my wife for help. First she tried with her right hand-nothing. Then she tried with her left hand-nothing. She even tried with her mouth, first with her teeth in, then with her teeth out-still nothing. Finally we called the lady next door and she tried with both hands and her mouth too - and still nothing."
The doctor was shocked. "Your neighbor?"
"Yep. No matter how hard we tried, we just couldn't get that damned jar open!"