"Doctor I think my son has syphilis," a patient told his doctor. "But you see the only person he has had sex with is our neighbor's daughter".

"Don't worry," the doctor assured the patient. "He's just a kid and sometimes mistakes happen. Bring him in and I'll take care of him".

"But doc, I had sex with the neighbors' daughter as well and I'm starting to get similar symptoms".

"Then you both come in and I'll see what I can do".

"I think my wife might have it too" the guy said.

"Son of a bitch!," the doctor shouted. "That means we all have it".