Do parents really know the deal when it comes to their kids and sexting? John Walsh, host of "Americas Most Wanted" said they don't have a clue.

That’s why it’s incredibly important to sit down with your child and talk about the dangers of this growing problem, Walsh told FOX and Friends Thursday morning.

“I talk to my 14-year-old son — but the bad news is that 1 in 4 teens say ‘hey, hey hey… parents don’t know what the heck they’re talking about… and every teenager thinks they’re bullet proof,” Walsh said. “But when that picture shows up in cyberspace, and that college admissions director sees that looking at the Myspace page or the Facebook page — or they hear about it, or the kid gets arrested for distributing a sexy picture — you know — then it’s going to come back to haunt that kid.”

VIDEO: Lawsuit in wake of 'sexting' case.

And while many parents may shake their head and say, “not my kid,” they better wake up – because it’s become shockingly popular among America's youth.

A new survey, conducted by The National Campaign to Prevent Teen and Unplanned Pregnancy and CosmoGirl.com, uncovered some alarming figures. The survey of more than 1,200 volunteers aged 13 to 26 found that 20 percent of teenagers have either sent or posted nude or semi-nude pictures or videos of themselves, while another 48 percent said they have received such messages.

Click here to read the full study (pdf).

Sixty-six percent of teen girls and 60 percent of teen boys say they did so to be “fun or flirtatious” – which was their most common reason for sending racy content.

“Go to www.cox.com/takecharge. It gives parents like you and I great information of how to sit down and talk to your kid, and not in a condescending or demeaning way. Find out what your kids are doing and sit down and say, ‘look, that picture will be online forever. You think it’s cool but it’s not cool because that picture is going to be up there forever."

The bottom-line: Take that time no matter how busy your schedule is to talk to your kids, Walsh said.

“Find out about the dangers on the Internet and sit down with your kids,” he added.

For more than two decades, Walsh has been making sure the nation's most notorious criminals are brought to justice. His activism was spurred by the abduction and gruesome murder of his 6-year-old son, Adam, in 1981.

Since then, the case has contributed to massive advances in police searches for missing children and led to the start of "America's Most Wanted."

Click here to see Walsh on FOX and Friends.