A couple tried for a while to conceive a child but had no luck. So, they went to the doctor. The doctor, whose name was Dr. Bogovian, but that's not important, advised them to continue trying on their own, but they were sure there was a clinical reason for their infertility. So the doctor examined the woman, whose name was Sarah, ran a few tests, and determined she could in fact get pregnant. The doctor then wanted a sperm sample from the man, whose name was Ralph. He gave the couple a sealed sterile jar, and sent them into an exam room to get the sample.
They were in the room for an hour, and it was time for the clinic to close when the couple finally came out. They looked very embarrassed, and produced an empty jar. The doctor looked at the jar and asked if there was some problem. The man looked dejectedly at the ground and said,
"Well, doc, I hate to admit I had a problem with this. I tried, but my hands are really tired. I tried with my left hand, I tried with my right hand, I tried with both hands, nothing. So my wife tried to help me, and then SHE tried with her left hand, and tried with her right hand, she pulled and pulled, but it just didn't help.
"Then we found some vaseline in a cabinet. She rubbed it really good under the edge but that didn't help either. She tried using her mouth, but after trying that for a while, she just ended up with a sore jaw. We couldn't figure out what else to do, so we came out here."
The doctor said, "Do you often have a problem with impotence?" The man said "Impotence!? Hell no, doc, we couldn't open the damn jar!"