The Automatic Diagnosis Machine

A man goes to the doctor complaining about pain in his elbow. The doctor has him pee in a cup and then takes the sample and dumps it into a small machine. After a few seconds the machine spits out a piece of paper, the doctor looks at it and proceeds to tell the man that he has tennis elbow, to take a few aspirin and to ice his elbow down every night.

The man is pretty incredulous that this machine could diagnose all this from a urine sample, so he decides to test it. That night he goes home and has his wife, daughter, son, and dog all pee in the cup. Then to make it interesting he adds a little motor oil from the car, and to top it off he masturbates into the cup as well. The next day he goes back to the doctor, who puts the sample into the machine. This time the machine churns out a much longer piece of paper.

The doctor looks at it for a while then says, "I have some bad news and some good news. The bad news is that your wife is having an affair, your daughter is pregnant, your son is using heroine, your dog has rabies, and your car needs a new transmission. But as for the good news, if you stop jerking off so much, that tennis elbow should clear right up."