A young man went to a party and met a very attractive young blonde. She seemed very agreeable and after a few drinks she invited him to her apartment around the corner. Soon they were naked, and she told him that she had been to the doctor that day and diagnosed to have a disease. But she couldn't remember what.
"Do you have any idea", asked the man. "It started with an 'a'. It was either AIDS or arthritis. I can't remember which", said the women.
Quickly the man called a doctor friend of his. But the friend couldn't do the diagnosis over the phone. "But I have an idea", said the doctor. "Chase her around the room a little, and if her joints swell then make love to her."