More than half of 10th graders have used alcohol in the past year; more than a quarter have smoked marijuana, according to a recent study. These are figures that parents readily believe are true, but when it comes to their own kids, these moms and dads say they never touch the stuff. According to a study by the University of Michigan, about 10 percent of parents believe their teenage children have consumed alcohol in the past year, and 5 percent believe they’ve used pot—both far lower numbers than the students themselves report. The implication, of course, is that many parents don’t have a very good idea of what their children are getting into. “Awareness is a means of opening the door to communication,” says Bernard Biermann of the University of Michigan. “If parents acknowledge the possibility—and in fact, the likelihood—that their child may have experimented with or used alcohol or marijuana, they can begin to talk to them more about it, provide some guidance, and allow their kids to ask questions.” (LiveScience)