Online communication is extremely popular among teens, but you might be surprised to find out that what 13-year-olds actually do. The most recent survey by The National Campaign to Prevent Teen and Unplanned Pregnancy and CosmoGirl.com revealed that one in five teens admitted to sending or posting online nude or semi-nude images of themselves. At least one in 10 girls aged 13-16 have admitted to the same behavior.

Out of the 1,280 teens and young adults taking part in the survey, at least 15 percent of them have sent sexually suggestive content via text messages, emails, photographs or videos to persons they only know online, but not in real life. Furthermore, at least one third of teen boys and one fourth of teen girls said they have had nude images shared with them, even though they were intended to be private.

Taking and posting semi-nude or nude images of themselves is not a behavior restricted to either sex, and the percentages go even higher for young adults, aged 20-26.

The report also found that nearly half of young people have sent sexually suggestive text messages or email messages to someone. In addition to that, 48 percent of teens and 64 percent of young adults said they have received sexually suggestive messages. What's worrisome is that one third of young girls, aged 13-16, have received such messages as well.

The question is what do they get from posting these images? The report provides an answer to that: 22 percent of teens admit technology personally makes them more forward and aggressive, while 38 percent of teens say exchanging sexy content makes dating or hooking up with others more likely.

Two thirds of teen girls who have sent or posted sexually suggestive content said they did it in order to be “fun or flirtatious,” 52 percent of them did it as a “sexy present” for their boyfriend, and 40 percent of them did it as a joke.

However, 51 percent of teen girls also said that they posted or sent the sexy messages or pictures following pressure from a boy, while only 18 percent of teen boys said they were pressured by their female counterparts.

According to Marisa Nightingale, Senior Advisor to the Entertainment Media Program at the National Campaign to Prevent Teen and Unplanned Pregnancy, parents need to understand that their notions of what’s public, what’s private and what’s appropriate greatly differ from how teens and young adults define the concepts.

Furthermore, Nightingale said, the fact that so many young people consider technology to be encouraging a more casual, hook-up culture should be a reason of concern, especially considering the high rates of teen and unplanned pregnancy in the United States.

While most young people (73 percent) said sending sexually suggestive content “can have serious negative consequences,” 22 percent of them consider it to be “no big deal.” According to the survey, almost 90 percent of teens and young adults use the Internet.