Nearly half of America’s teenagers are using their cell phones to send photos and messages their parents would find unacceptable or even downright dangerous — if, that is, the parents had a clue about what’s going on right under their noses. That’s from a new survey by Family Circle magazine, which queried both teens and their parents about teens’ social lives. The survey found that 45% of teens admit to sending inappropriate stuff, while 78% of moms and dads believe their child has never done anything of the kind. “Parents need to educate themselves about what is going on in their teen’s world,” said Family Circle’s health director, “as teens are much more likely to listen if you talk to them about [modern life] in an open and honest way.”