"Doctor," the embarrassed man said, "I have a sexual problem. I can't get it up for my wife anymore. I think I have erectile dysfunction."
"Mr. Thomas, bring her back with you tomorrow and let me see what I can do."
The next day, the worried fellow returned with his wife. "Please take off your clothes, Mrs. Thomas," the doctor said. "This is necessary for me to evaluate your husband's condition. Now turn all the way around. Lie down please. Uh-huh, I see. Okay, you may put your clothes back on."
The doctor took the husband aside. "You're in perfect health," he said. "Your wife didn't give me an erection either."
It sounds like that should be "Mr. Smith," not "Mr. Thomas" ; P