Why is there so little scientific information about anal sex?

Twenty years ago, 25-30 percent of young people reported that they had tried anal sex. Today, a recent survey shows that 40-45 percent have tried it. Anal sex is more popular among Americans than ever before, but there are almost no medical studies on its effects. Indiana University sex educator Debby Herbenick has… » 10/10/12 3:20pm 10/10/12 3:20pm