Are we legally responsible for what our kids do on phones WE bought them and computers WE pay for? A leading bullying expert and attorney weigh in.

In an unusual legal case arising from the increasingly popular practice known as "sexting," six Pennsylvania high school students are facing child pornography charges after three teenage girls allegedly took nude or semi-nude photos of themselves and shared them with male classmates via their cell phones.

The female students at Greensburg Salem High School in Greensburg, Pa., all 14 or 15 years old, face charges of manufacturing, disseminating or possessing child pornography while the boys, who are 16 and 17, face charges of possession.

This got us thinking ... if parents are paying for these phones, are we legally liable for what our kids do on them?

To find out, we spoke with attorney Robin Sax, a former Los Angeles County Deputy District Attorney who specialized in prosecuting sex crimes against children. She's the author of six books, including Predators and Child Molesters: What Every Parent Needs to Know To Keep Kids Safe.

"You first have to separate the two justice systems -- civil liability and criminal liability," she says. "Criminal culpability is what most people are concerned about. They think, 'Am I going to have to go to jail and register as a sex offender if my kid did something on his cell phone or on my computer?'"

She says prosecutors might know a picture was sent from your kid's phone (that you pay for), but don't know exactly who sent it. "I think they would have a hard time charging the parents in that case," Sax explains. "Even if you own the phone, that doesn't make you criminally liable unless you sent the picture yourself. And they would have a hard time proving the parents sent the picture beyond a reasonable doubt."

However, she says you could possibly face a civil suit. "From a civil point of view, the parents could potentially be sued. In a civil suit, they're going after the money -- and who has the money? The parents," she says. "The standard of proof is much lower in a civil suit. If you own the phone and you pay the phone bills, you're deemed to have ownership and control, so you could be found liable. Also, do parents have a duty to protect and monitor their child? This might also come into play during a civil case."

What happens online is also a legal concern for parents. Mom Lori Drew was found guilty of three counts of gaining unauthorized access to MySpace for the purpose of obtaining information on Megan Meier, a 14-year-old who later committed suicide. In that case, Drew definitely played an active role in the harrassment. But what if your teen harrasses someone online and you have no knowledge of it?

Sax says the same rules apply -- a criminal suit against you is unlikely, but a civil suit could be a possibility.

Rosalind Wiseman, author of Queen Bees and Wannabes: Helping Your Daughter Survive Cliques, Gossip, Boyfriends, and Other Realities of Adolescence, says the laws regarding kids' behavior online and parental responsibility are constantly evolving, "The laws are coming down fast and furious," she says. "I'm always getting updates. It's a hugely changing, moving, dynamic thing."

She says kids' use of technology is so interconnected to the way they communicate, she doesn't even teach separate "cyber-bullying" classes or seminars anymore. "It's interwoven into every single thing they do," she says. "From age 5 or 6, they're on Webkinz. By third, fourth, and fifth grades, it's Club Penguin. By sixth grade, it's iPhone, iTouch, cell phones and texting. There's no way to talk about bullying WITHOUT mentioning technology."

She says parents don't necessarily have to install Spyware and monitor their kids' every move, but they should have all their kids' user names and passwords. Wiseman says parents should also let their children know that they reserve the right to check their online profiles or cell phone at any given time. "You can say, 'Look, I have a life, and I don't want to be constantly reviewing what you do. But I do reserve the right to check this when I want,'" Wiseman advises. "A little bit of paranoia and fear in a kid is a good thing."

She says Monday is a good time to check the phone (right after the weekend), as well as any time "your mom gut is going off."

At some schools she works with, Wiseman says the coaches even make kids give them their Facebook user names and passwords so coaches can closely monitor their pages. If students don't hand over that information, they can't play.

Do you think moms should be criminally liable for what kids send from their phones or post online?

Rosalind Wiseman is an internationally-recognized author and educator on children, teens, parenting, bullying, social justice, and ethical leadership. She is the author of several books, including the New York Times bestseller "Queen Bees and Wannabes: Helping Your Daughter Survive Cliques, Gossip, Boyfriends, and Other Realities of Adolescence" that was the basis for the movie "Mean Girls." She lives in Washington, DC with her husband and two sons.

Robin Sax is a former Los Angeles County Deputy District Attorney who specialized in prosecuting sex crimes against children. She is the author of six books, including "Predators and Child Molesters: What Every Parent Needs to Know To Keep Kids Safe". Robin lives with her husband and three children in Los Angeles, California.