Before you freak out, take note that doctors aren't talking about your comfy ballet flats. This is all about those pointy-toed flats that crowd your toes, causing everything from ingrown toenails which could cause a bone infection if left untreated to pronated bones that become bunions. Add to that December's much buzzed-about French study that found that men were more responsive to women wearing 3.5-inch heels, and you have more than enough reason to strap on those sandals—as long as they're not too pointy or narrow, of course.