Porn’s new pervasiveness and influence on the culture at large haven’t necessarily introduced anything new into our sexual repertoire: humans, after all, have been having sex—weird, debased, and otherwise—for quite a while. But pervasive hard-core porn has allowed many people to flirt openly with practices that may have always been desired, but had been deeply buried under social restraint. Take anal sex: in a 1992 study that surveyed sexual behaviors, published by the University of Chicago, 20 percent of women ages 25 to 29 reported having anal sex. In a study published in October 2010 by the Center for Sexual Health Promotion at Indiana University, the instances of anal sex reported by women in the same age cohort had more than doubled, to 46 percent. The practice has even made its way into the younger female demographic: the Indiana study shows 20 percent of 18- and 19-year-olds have had anal sex at least once.