There was a man whose elbow hurt, so he told his friend he was going to the doctor. His friend told him to go to the pharmacy, where there was a machine that for $10 and a urine sample could tell him what was wrong with him. So, he went, put his money and the sample in the machine, and it told him that his elbow just needed to be soaked in warm water for 2 weeks. That night, he decided that the machine must be a fraud.
The next day, he went back to the machine with a mixture of tap water, his dog's urine, his daughter's urine, and just for the heck of it, a sample of his semen. After working for a little while on the sample he had put in, the machine slid out a a piece of paper that said
"Your tap water has lead in it, your dog had worms, your daughter is on drugs, and she's not your daughter."