Dr. Samuel Kuperman at the University of Iowa said a teen's friend might be the biggest risk factor for starting drinking ahead of family history and social behavior.
Kuperman said drinking at a younger age is associated with illegal activities.
"Children oftentimes do things they wouldn't do if they weren't drunk," Kuperman said in a statement. "So, driving, getting into sexual activity, using other drugs, are all risks that might happen when somebody's drunk versus not drinking."
Drinking before the age of 14 is also associated with a risk for young adult alcohol dependency problems, Kuperman added.
Kuperman suggested talking to kids about drinking and its consequences.