Back rubs, slumber parties, holding hands, and playing with each others’ hair: This is all typical teenage girl behavior. While boys tend to rough-house, girls tend to be more affectionate. It’s always been innocent. Until now, that is, writes Washington Post writer Laura Sessions Stepp. Nowadays, “sexual preference is a shifting concept” among adolescent girls, and in our sex-charged culture affectionate behavior between girls has gone well beyond child’s play. It’s hard to tell whether these girls are acting on attraction or are simply vying for attention. For example, in one Washington, D.C., private school, a group of girls charged...