Nearly 30 percent of US teenagers are sexting, sending nude photos via e-mail or text, according to a new study.

More than half of teens have been asked to send a nude photo of themselves to someone, and 31 percent have requested a naked picture, researchers at the University of Texas found.

“Sexting is a prevalent behavior among teens, and it may be a fairly reliable indicator of actual sexual behavior,” said lead author Dr. Jeff Temple.