A new study demonstrates why parents need to know how their teenage girls present themselves online.

The study, published in the June issue of Pediatrics, shows that teen girls who would depict themselves online in a provocative way, and teen girls with a history of child abuse, are more likely to receive online sexual advances and then meet those individuals offline.

Moreover, 40 percent of all 173 teen girls in the study reported experiencing online sexual advances, and 26 percent reported meeting someone in person who they first met online.

The importance of parental monitoring of adolescent Internet use cannot be understated, says Jennie Noll, PhD, a psychologist at Cincinnati Children's Hospital Medical Center and the study's main author. This is particularly important given that 55 percent of adolescent Internet users have or are currently using social networking Websites.

Dr. Noll studied girls between the ages of 14 and 17. Each was asked to create an avatar -- an electronic image to represent herself -- and complete a questionnaire regarding her computer and Internet usage, sexual attitudes and activities, substance use, involvement with peers, and presence of maternal and paternal caregivers.

The avatars they created were evaluated based on previously defined categories spanning a continuum from conservative to provocative, depending on such factors as bust and hip size, upper body clothing, lower body clothing and piercings. Those who had depicted themselves as provocative in terms of body and clothing choices were more likely to have had online sexual advances.

In addition to choosing a provocative avatar, other risk factors for online sexual advances included substance abuse and being preoccupied with sex and sexual thoughts. Associating with high-risk peers was an additional risk factor for in-person encounters.

The Proteus Effect, or the idea that one's presentation of oneself can affect the behavior of the presenter as well as of the receiver, has important implications in this age of wide reliance on Internet use, where users can portray themselves in a multitude of fashions, says Dr. Noll. Self-presentations can change the way Internet users interact in a manner that increases the risk for online sexual advances. Your behavior can change based on how you present yourself to the world. It isn't just naive kids who are vulnerable. Those who choose to present themselves as 'sexually sophisticated' are particularly vulnerable to those who would choose to be exploitive of such self descriptions.

The presentation of oneself in a provocative manner, however, is not necessarily limited to Websites that rely on avatars as the primary interface. For female adolescents in particular, self-presentations such as a compilation of photographs and narrative descriptions on networking sites such as Facebook and MySpace might also increase their vulnerability, according to Dr. Noll. Some adolescents include content on their social networking face pages that is alarmingly provocative and revealing. These are the snapshots that are revealed publicly, for all to see.

Those adolescents who may be unaware of how their appearance might be perceived may not, from a developmental perspective, possess the social sophistication necessary to field and ward off sexual advances in ways that protect them from sexually explicit suggestions, she says. This may be a particularly important lesson to convey to female adolescents who are especially vulnerable to exploitation and victimization, such as those who have been victims of childhood abuse.

Parents can play an important role in preventing exposure to online sexual solicitations, according to Dr. Noll, who found that caregiver presence was associated with significantly fewer reports by adolescents of online solicitations. For example, she says parents should emphasize to adolescents ways to ward off sexual advances and explain to them how virtual self-representations can influence behaviors and perceptions.

Primary care physicians, too, should consider asking teen patients about their Internet use as an aspect of comprehensive care. Not enough people are talking about how teens are being proactive in putting themselves out there for public consumption, according to Dr. Noll.

In many respects, reacting to normal urges and curiosities about sex is a large part of normative adolescent development, but doing so via virtual personas or provocative self-descriptors in social networking worlds may not be the healthiest or most safe avenue by which to explore, she says.

The study was supported by a grant from the National Institutes of Health.