Parents trying to raise faithful, virtuous, principled kids need to manage the media they consume, and that includes social media. According to the Pew Research Center, 89 percent of teens use social media.

Many young people live their lives out on sites such as Instagram, Snapchat and Facebook – or, at least, they portray the lives they want their peers to see. And that’s part of the trouble. For many, sharing on social media isn’t about expressing who they really are, it’s about creating a persona. It can leave tweens and teens little time – or inclination – to reflect on who they really are or who they want to become. On top of that, kids can feel compelled to track what everyone else is doing, often in real time.

In a piece for The Atlantic, psychologist Jean Twenge writes about this. “For all their power to link kids day and night, social media also exacerbates the age-old teen concern about being left out. Today’s teens may go to fewer parties and spend less time together in person, but when they do congregate, they document their hangouts relentlessly – on Snapchat, Instagram, Facebook. Those not invited to come along are keenly aware of it. Accordingly, the number of teens who feel left out has reached all-time highs across age groups. Like the increase in loneliness, the upswing in feeling left out has been swift and significant.”

Twenge adds that social media puts a burden on those doing the posting, too, as they await affirmation in the form of comments and “likes.” She calls it a “psychic tax.” Social media ramps up the peer pressure most teens already feel to fit in with the crowd. That can make it especially difficult for Christian teens trying to live out their faith.

According to TeenSafe, Snapchat is the fastest growing social media app at the moment, with four out of 10 teens making use of it. It has an estimated 82 million users, most of them between the ages of 13 and 25. Here’s how it works: users can send photos or videos along with text messages which then disappear from the receiver’s phone within a few seconds after being viewed. According to TeenSafe, the app has become a hotbed of sexting and cyberbullying, in part because it’s anonymous.

So what’s a parent to do? As I write in my new book, Don’t Let the Culture Raise Your Kids, parents need to take charge of the media in their children’s lives, including digital media in the form of social networking sites. Be “friends” with your children on Facebook, and “follow” them on all social media. Chances are you’re paying for the smartphones, tablets and laptops your children use, so set up ground rules from the start. Insist on knowing passwords and logins. Make sure your children understand that having and using those devices is a privilege, not a right. Wait for as long as possible before giving your kids access to the internet. When you do, use filtering software. Some programs allow parents to block kids from downloading apps.

Sexting has become too common for Christian parents to ignore. At an appropriate age, discuss the issue with your children. Urge them to share with you any sexting incidents or issues they encounter. As with so many problems facing parents and their children, making rules and encouraging child-parent dialogue are critical.

For parents concerned about violating their children’s privacy when it comes to knowing what they’re doing online, here’s some advice from Leonard Sax, a pediatrician, psychologist and author of Girls On The Edge: “You wouldn’t let your fifteen-year-old daughter, much less your 10-year-old daughter, go to a college fraternity party by herself. By the same token, although for different reasons, you should now allow your daughter to engage in online social networking without your supervision.”

And here’s some advice from a priest in Norfolk, Virginia, who sent out this tweet: “Dear Parents: Get Snapchat off of your kids’ phones. Now. Don’t ask. Just do it. Let them hate you. That will pass. Love, a priest who hears their sins.”

There is also the matter of influence. The more time children and teens spend consuming social media, the greater the influence of their peers and of the culture in general. So make family time a priority. Do everything you can to have family meals together, and don’t allow cell phones at the dinner table.