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Before teenagers reach for the car keys, parents  should remind them about the dangers of using their cell phones or any other gadget while driving - this holds especially true for daughters.

A new study from the AAA Foundation for Traffic Safety says that when it comes to teenagers behind the wheel, the use of electronic devices - to text or to talk on a hands-free phone - is the No. 1 distracted-driving behavior.

In the final phase of a three-part study that used data recorders in the cars of 50 North Carolina families with a novice teenage  driver, researchers examined six months of video clips for each family.

A total of 52 drivers were recorded - 38 of whom  had just received their licenses, and 14 teen siblings.

In nearly 8,000 clips,  electronic devices were used  nearly 7 percent of the time, accounting for more than any other distracted-driving behavior,  such as adjusting controls, eating and drinking or turning around.

And girls were the worst offenders. In video clips, they used electronic devices 7.9 percent of the time, while boys clocked at 4 percent. The time of day or day of week did not affect distracted-driving behavior.

The study also found that teenage drivers were three times more likely to take their eyes off the road when using these devices.

Carol Ronis, the foundation's senior communications manager, said the study was important because car crashes remained the leading cause of death for teenagers  in America. Teen car crashes are roughly four times higher than they are for adults.

"We know that teen drivers are avid users of cell phones and other technologies," she told ABC News today. "Continue the conversation with your child. Set a good example. They are always watching and modeling our behaviors."

Her advice: "Keep your hands on the wheel, eyes on the road and mind on the task."