ROUGHLY one in every 100 teens has engaged in so-called sexting, the sending of sexually explicit pictures of oneself via digital media, in the last year, according to a new study. But the senders who intended the images to be an intimate message for one special recipient may be surprised: 7.1 percent of Internet-using teenagers told the authors of the study that they had received at least one such image on their phone or computer in the last year.

The study, published in the journal Pediatrics, concluded that sexting is not as common as many parents may think because of widespread reporting on the trend, legal actions against some who engage in it and, in some cases, unfamiliarity with kids' digital worlds.

"The data suggest that appearing in, creating, or receiving sexual images is far from being a normative behavior for youth," wrote the authors, from the University of New Hampshire's Crimes against Children Research Center.

The study is based on a survey of 1,560 children, 10 to 17 years old, who use the Internet. Older teens were far more likely than younger children to create and send sexual images of themselves, or to receive them. The survey found that children defined sexting more broadly than adults do and that a substantial minority - about 28 percent - of those making or receiving such messages reported them to adults or authorities or were caught getting or sending the messages.

Questions designed to elicit details of such messages suggest that most are produced as a prank or in the context of an existing romantic relationship, and that many "sexts," as defined by teens, include pictures that show underwear, clothed genitals or skimpy bathing suits. Roughly 3 in 10 were created in instances where alcohol or drug use was an aggravating factor.