An old man visits his doctor who says he needs a sperm sample.

He hands the old man a jar and brings him to a private room.

After 1 1/2 hours the old man comes out and hands the doctor an empty jar.

Doctor: “What happened?”

Old Man: “First I tried with my right hand. Then my left hand. Then with both hands.”

“No matter what I tried I couldn’t get the lid off that jar.”