A new study released Thursday by the Centers for Disease Control and Prevention found that although the number of U.S. teens having oral sex remained high, the rate was considerably lower when scientific researchers were openly observing them. 'When teenagers were by themselves, with nobody from the scientific community in the same room with them closely watching their sexual behavior, our findings indicate that 47 percent of them engaged in oral sex,' CDC spokesman Miles Dalton told reporters during a press conference. 'However, when the adolescents were being watched by researchers, that number dropped as low as 3 percent. Moreover, when scientists, clipboard in hand, told the teenagers that they wouldn't mind at all or be offended if they began having oral sex right there in front of them, that number rose only slightly to a still very low 5 percent.' According to Dalton, the rate of teenagers willing to engage in anal sex while alone or while being observed by scientists was, in both cases, 89 percent. 