A world famous urologist believed he could diagnose any disease simply by looking at a urine sample. To test his prowess, a friend with tennis elbow peed into a jar and then got additional donations from his wife, daughter and his dog.
The next morning , he jerked off in it as well.
He gave the bottle to the famous urologist and was told he'd called in a few days with the results.
Finally the urologist called and said, "It was tough case but I think I've solved it."
"What wrong with me?" the man asked.
"Well, your wife has the clap, your daughter is pregnant, your dog has worms and if you quit playing with yourself, you wouldn't have tennis elbow."