The Second Opinion

A guy was having a real bad pain in his elbow, so after a couple days he goes to the doctor to get it checked out. The doctor examines him and tells him he has tennis elbow.
"That's impossible doc, I don't play tennis" he says.
"That's besides the point, you still have tennis elbow" says the doctor.
"Well I want a second opinion" says the man.
"Well your in luck" says the doctor "we have this new machine, just came in. All you have to do is give me a urine sample, I pour it into the machine and it tells us everything wrong with you."
"I'll try it, but I don't have to go now. Can I bring it back tomorrow?" he asks.
"Sure" says the doc and hands him a cup.
That night, after a few drinks, he gets up to 'fill the cup'. After pissing he gets a great idea and has his wife piss in the cup. Then he has his son piss in the cup, his daughter piss in the cup, his dog piss in the cup, then he puts a little oil from his car in the cup, and for good measure yanks a glob in the cup.
The next day the guy returns to the doctors office with the infamous cup. The doctor pours the cup in the machine and after a few minutes out comes a printout with the results.
"Well" says the doctor "it says here that your wife has herpes, your son has AIDS, your daughter is pregnant, your dog has parvo, your car needs a tune-up, and if you don't stop jerking off your never getting rid of this tennis elbow."