If you're parent, pay attention to this. One in five teens have sent sexually explicit photos or videos from their cell phones and a third having received such images, according to a new study.  "Sexting" is on the rise as more teens send nude images to their friends and sometimes strangers.

"Teens are impulsive, they do what their friends are doing and they don't think about what may happen later on down the road" said Dr. Steven Tobias, a psychologist at the Center for Child and Family Development in Morristown.

But its not just teens sending these types of messages to one another. Adults are doing it too.  One in ten people age 55 and older have also sent sexually explicit images or videos to someone.

"Its becoming normal behavior for many many people" said Tobias.

He said teens don't seem to care about the potential consequences.

"I said to a girl...would you consider walking down the halls of your school naked...and she said of course not, and I said well that's basically what you did."

Only three percent of those surveyed said their biggest concern about losing their phone is that inappropriate pictures or texts might be exposed.

"That's very troublesome" said Tobias.

How do you talk to your teen?

- Be sensitive to peer pressure.

- Talk to them now before they engage in sexting and realize that your child is probably doing it even if they say they aren't.

- Explain to them the consequences of phone use if you find such images and remind them that once a message is sent it lives forever in cyberspace.