Connor Perruccello-McClellan, a senior at Providence Country Day School in Rhode Island, has been vaccinated against HPV, something less than 1 percent of U.S. males can say. Richard Knox/NPR hide caption

itoggle caption Richard Knox/NPR

Pinwheels like these are often used to test nerve responses. iStockphoto.com hide caption

itoggle caption iStockphoto.com