TUESDAY, Oct. 30 (HealthDay News) -- Teens with smartphones are more likely to have sex and meet others online for sex than teens without Internet access on their phones, according to a new study.

But it's not clear if the smartphone actually influences teenagers' sexual activity, and at least one critic of the research called it weak.

Still, the smartphone is "one of the tools that risk-taking teens are going to use to take risks," said study co-author Eric Rice, assistant professor at the School of Social Work at the University of Southern California, in Los Angeles. And he thinks there's "definitely a connection" between having the phones and having sex.

For the study, the researchers surveyed more than 1,800 high school students aged 12 to 18 from Los Angeles public schools. Many were from middle- and low-income families.

One-third of the students owned smartphones, such as iPhones and Blackberries, that provide access to the Internet and software apps in addition to text-messaging and camera capabilities that are basic on many cell phones. Essentially they are mini-computers and cell phones in one.

Forty-seven percent of these students said they were sexually active, compared to 35 percent of those who didn't own smartphones.

Seventeen percent of the smartphone users said they had had sex with someone they met online, compared to 14 percent of kids without smartphones, Rice said.

Although smartphones, like cell phones, let parents keep track of their children, they also give kids private access to the Internet, Rice said. "You can get online relatively unsupervised and look for sex partners or have sex partners look for you," he said.

It's not clear, however, how kids might do that. The study didn't ask about websites they visited.

The study also doesn't prove that smartphones and sexual activity are connected, or look at whether being sexually active might make kids more likely to use smartphones rather than the other way around.

David Finkelhor, director of the University of New Hampshire's Crimes Against Children Research Center, questioned the findings.

"Youth with smartphones could be having more sex for many reasons that have nothing to do with smartphones," he said. "I would be willing to bet that youth with cars are more likely to have sex too. This research is sure to be misinterpreted as an argument for limiting smartphone access."

As for the idea that finding sexual partners on the Internet can be dangerous, Finkelhor said "there is no research I know of that suggests that it is riskier to seek sexual partners on the Internet than elsewhere. Bars and parties may be much riskier environments."

It's possible that "the Internet and smartphones can even improve quality of judgment," he said, perhaps through the popularity and success of dating sites. The sites allow people to learn many things about potential dates before they meet in person.

Rice, the study co-author, recommended that parents have discussions with kids about online predators, sexually transmitted diseases and birth control.

"I would urge parents not to panic but use this as a moment to think about having a dialogue," he said.

He also said that social-networking websites such as Facebook represent logical places for sexual-health programs that target teens.

The study is scheduled for release Tuesday at the American Public Health Association's annual meeting in San Francisco. Research and data presented at medical meetings are typically considered preliminary until published in a peer-reviewed medical journal.

More information

For details about teen sexual health, see the U.S. National Library of Medicine.