“It only takes one or two cases to make people think this is very prevalent behavior,” said Janis Wolak, an author of the new paper and a senior researcher at the Crimes Against Children Research Center at the University of New Hampshire. “This has been reported as if it were something that everyone was doing, not just in the teen population, but in the young adult population. It’s really not the case.”

Over all, the new report found, 149 youths interviewed for the study, or 9.6 percent, said they had sent or received images that included full or partial nudity in the previous year. Just over 2 percent of those who engaged in sexting said they had appeared in the pictures or had taken them themselves, and 7.1 percent said they received sexual images from someone else.

In most cases, the motivations for sending or forwarding sexual texts were not malicious. Most of the youths who sent such messages said that they did so with someone they were involved in a relationship with, or that their messages were flirtatious gestures to someone they had a romantic interest in.

About 31 percent who appeared in or took sexual images said that alcohol or drug use had been a factor. And despite public concerns about lewd photographs of minors that start out as private messages becoming widely distributed, only 3 percent of the minors in the study said they had forwarded sexual photographs that they had received.

The fact that about a third of sexual messages were created or sent when alcohol or drugs were involved suggests that the children who are doing the riskiest messaging are engaging in other risky behaviors as well, said Nancy Baym, a professor of communication studies at the University of Kansas and author of the book “Personal Connections in the Digital Age.”