THURSDAY, June 30 (HealthDay News) -- About two-thirds of Internet sexual offenders bring up the topic of sex during the first chat session with adolescents and young adults, a new study has found.

This and other findings highlight the dangers that social networks can pose to some young people, according to the researchers who conducted the study, reported in the July issue of the American Journal of Nursing.

"The use of online social networks such as Facebook continues to rapidly increase among all age groups, providing new opportunities for the exchange of sexual information and potential unsafe encounters between predators and the vulnerable young," lead author Elizabeth B. Dowdell, associate professor at Villanova University College of Nursing in Pennsylvania, said in a journal news release.

She and her colleagues analyzed questionnaires completed by 404 middle school students (ages 9-15), 2,077 high school students (ages 15-18), 1,284 students at four-year colleges, and 466 men who had been convicted of either an Internet sexual offense or a hands-on sexual offense and/or a prior Internet offense.

Among the other findings:

  • More than half of the Internet sexual offenders said they disguise their identity when online, and most said they prefer communicating with teen girls rather than boys.
  • More than half of the high school girls (56.7 percent) in the study knew about sexting (sending sexually explicit messages or photos electronically), compared with 46.9 percent of boys. Private school students were more likely to know about sexting than public school students -- 75 percent versus 50 percent.
  • Of the 59 middle school students who said they chatted with strangers online, 32 of them said they had met the stranger in person, and three of these said they were sexually assaulted or inappropriately touched.
  • Of the 51 high school boys who said they had a face-to-face meeting with a stranger they met online, 33 said "something sexual" (consensual) happened, and 10 reported being threatened or sexually assaulted.
  • Of the 58 high school girls who said they met in person with a stranger they met online, 21 said something sexual happened and seven said they were threatened or sexually assaulted.

More information

The FBI offers a parents' guide to Internet safety.