According to a new Australian study, teens who start drinking before age 15 could jump-start any genetic conditions they might have that predispose them to developing alcohol dependency.

The findings, published online Sept. 18 and in the December print issue of Alcoholism: Clinical & Experimental Research, are based on a study of 6,257 adult twins. The younger people were when they had their first drink, especially if that occurred before age 15, the more symptoms of alcohol dependency they developed, the study found. Early drinkers also tended to have an increased genetic vulnerability for alcohol.