A new study shows that the use of smartphones is associated with an increased likelihood both of teens being solicited for sex via the internet and of having sex with someone they met online.

The study was conducted by researchers at the University of Southern California’s School of Social Work and presented this week American Public Health Association’s 140th annual meeting in San Francisco. It looked at a survey of 1,839 students from age 12 to 18 in the Los Angeles unified School District. Overall, around one-third of those surveyed reported using their phone to access the internet. The results were controlled for a variety of factors, including age, race, gender, and sexual orientation.

The findings show that teens with smartphones are 1.5 times more likely to report being sexually active. The study also shows that teens with smartphones are nearly two times more likely to have been approached for sex via the internet and two times more likely to have engaged in sex with someone they met online. 5% of of those surveyed reported using the internet to find sex and 17% reported being approached for sex by a stranger over the internet.

“We – parents, health educators, physicians – must recognize that cell phones are yet another new way for adolescents to meet sex partners,” said Hailey Winetrobe, a public health researcher at USC. “Parents and school health professionals should talk to their teens about being safe in meeting people online and in using condoms to prevent sexually transmitted infections and unplanned pregnancies.”

The researchers emphasized that the very channels that enable this type of behavior could be the same channels used to educate teens about sex. They stated that the internet and smartphone apps are “prime venues” for sexual health programs targeted at teens.