A man goes to his doctor to get a prescription for Viagra. The doctor looks over the man and says, "Viagra can be very dangerous and we do not just dispense it indiscriminately. Please bring your wife to my office next week and we'll discuss this in more detail."
So the next week the man shows up with his wife. The doctor asks to see the wife by herself for a few moments. So she follows him back to the examining room. The doctor asks her to disrobe and she does. He then asks her to turn around a few times. He then instructs her to get up on the examining table and to turn in various positions. He then tells her that she can get dressed, then goes out to meet the man. "Sir," the doctor says, "There is nothing wrong with you. I couldn't get an erection either!"