This is the right age to give your child a smartphone, according to an NYU mental health researcher

Parents around the world are debating when to give their children smartphones, as evidence grows that smartphones can have negative effects on the mental health of children.

Research indicates that young people's mental health was worse the earlier they got their first smartphone, according to a Sapien Labs study published last year, which used data from 27,969 18-24-year-olds across 41 countries.

Some 74% of girls who received their first smartphone at age six said they felt distressed or were struggling, the study found. This decreased to 52% for those who got their first smartphone at age 15.

Meanwhile, 42% of boys who got their first smartphone at age 6 experienced feeling distressed or struggling, and this reduced to 36% for those who received a smartphone at age 18.

But smartphones have become an essential part of everyday life in an increasingly online world and many parents want to give their children devices so they can keep track of their location and stay in touch with them when they leave the home. So how soon is too soon?

Zach Rausch, a research scientist at New York University Stern School of Business and the lead researcher for Jonathon Haidt's No. 1 New York Times bestseller "The Anxious Generation," said it's particularly important to keep smartphones away from preteens.

"We suggest in the book to delay smartphones in the U.S. until high school, so that's around age 14," Rausch told CNBC Make It in an interview. "Social media, we suggest delaying until 16, so a little older."

"Then we suggest phone-free schools from at least kindergarten through middle school in the U.S., but ideally also through high school," he added.

It comes as grassroots organizations advocating for delaying giving smartphones to kids are