Some 23 percent of those aged 12-17 say they have a smartphone, according to the Pew Internet and American Life Project.
When Janell Burley Hofmann's son turned 13, she faced a question: Was it finally time to give him a smartphone?
She decided he was responsible enough to handle it, but not without signing an 18-point contract regarding appropriate use of the iPhone.
"In the quiet of the night, I had my own anxieties about giving him this technology that would be the world at his fingertips," she tells NPR's Ari Shapiro. "What's in this contract is absolutely nothing that we haven't ever had a discussion about. ... I basically felt compelled to just put everything we've talked about to paper."
Hofmann posted the code of conduct she made for her son, Gregory, on her blog after she gave him the phone on Christmas, and it soon went viral. She and Gregory appeared on ABC's Good Morning America, and have received international attention.
The contract includes non-negotiable rules like, "I will always know the password," and practical advice like, "Keep your eyes up. ... Wonder without Googling."
It also touches on some more serious tenets. Point 10 is "No porn," and point 12: "Do not send or receive pictures of your private parts or anyone else's private parts. Don't laugh."
"[Gregory] had a good laugh at that," Hofmann says. "And that's why I even put in there 'don't laugh', because maybe right now, at 13, that seems preposterous." But maybe in college or something after ... I want this ... little voice in your head to be like, 'I remember that contract for my first iPhone.' "
Though her son had been asking for a while, Hofmann and her husband had hoped to delay the technology.
"We live in a very close-knit community," Hofmann explains. "I just didn't see the need."
They finally ended up giving in, mostly for practical reasons.
"In full disclosure ... we had a free upgrade," she says.
Hofmann received a lot of criticism for the piece. Some parents felt she was being too controlling, and others felt that posting the contract was too embarrassing for a teenage boy.
"When I sit with my son and look at his contract, I can just absolutely say this is something that's working for us," she says. "He never saw it as a violation of trust or privacy. And to be totally honest, he keeps saying, like, 'Hey, mom, what's all the fuss about?' "
Hofmann says she did not publish the rules to serve as commandments for every household, but shared them to encourage parents to talk to their children about technology.
"Certainly, you make changes to it," Hofmann says. "I expect that everybody knows what's best for their family. This just happened to work for mine."