Photo: George Burns/Harpo Studios

It's the question that is bound to start a debate within your closest circle of friends—Do you sleep with underwear on or off?

Dr. Oz says it's time to go au naturel. "You don't want it to be so moist down there. Let it dry out a little bit," he says. "Secondly, the underpants can abrade on your skin a little bit, which can cause pimples, and you don't want that."