HE THOUGHT he saw it out of the corner of his eye. Nah, couldn't have been. Then an adult aide in his classroom confirmed what the teacher had almost missed. "There were two girls in the front of the classroom [groping] each other," he recalled. "They had stopped by the time [the aide] called my attention to it. But that's what it was." And that's what it is, but not only at Fitzsimmons Middle School, in North Philadelphia, where this scene took place two weeks ago. There are about a half-dozen high schools and at least two middle schools where...