A girl goes into the doctor's for a checkup. As she takes off her blouse, the doctor notices a red 'O' on her chest. "How did you get that mark on your chest?" asks the doctor. "Oh, my boyfriend went to Oxford and he's so proud of it he never takes off his Oxford sweatshirt, even when we make love," she replies.

A couple of days later, another girl comes in for a checkup. As she takes off her blouse, he notices a blue 'C' on her chest. "How did you get that mark on your chest?" asks the doctor. "Oh, my boyfriend went to Cambridge and he's so proud of it that he never takes off his Cambridge sweatshirt, even when we make love," she replies.

A couple of days later, another girl comes in for a checkup. As she takes off her blouse, he notices a green 'M' on her chest. "Do you have a boyfriend at Manchester University?" asks the doctor.

"No, but I have a girlfriend at Warwick, Why do you ask?"