"I see about 15 butts a day, and a third of them have warts," says nurse practitioner Naomi Jay of the University of California at San Francisco. Jay and
infectious-disease doc Joel Palefsky were the first to run extensive clinical studies on the sexually transmitted diseases that afflict the anus. "He's the tushie king, and I'm the tushie queen," Jay boasts. Each of us has about a 10 percent lifetime risk of contracting anal warts, the worst
variety of which--enemy number one storming the battlements of Jay's royal domain--is human papillomavirus. This same STD that can cause cervical cancer in women also causes anal cancer in both genders. And the only way to detect this rare but deadly disease is to ask a highly trained nurse like Jay to scrutinize your derrire. "A giant anal wart can be a couple inches large and blocking the anal opening," Jay says with her customary vigor. The bright side? "In 13 years I've only been pooped on twice, and that's not bad."