A teen’s family structure influences whether allowing them to drink at home leads to alcohol problems later on, a new study suggests.

Teens living with both biological parents who were allowed to drink at home had the lowest levels of alcohol use and problems later on. Those living with either a single parent or in a blended family (such as a biological parent and a stepparent) who were allowed to drink at home had the highest levels of alcohol use and problems, according to The Boston Globe.

The study appears in the Journal of Studies on Alcohol and Drugs. It included 772 children ages 12 to 17, along with their parents. They were first interviewed in 1989, and were re-interviewed up to four times over the next 15 years. The researchers found being allowed to drink at home did not in itself predict later alcohol use, but family structure played a large role in moderating the relationship.

Previous studies that have looked at the consequences of allowing teens to drink at home have not examined the relationship between drinking at home and family structure, the article notes. Some studies have found teens allowed to drink at home had heavier alcohol use or higher rates of drinking problems, while others have found lower overall alcohol use.

“An intact family structure with two parents might serve as a proxy for factors like better communication with both parents and clearer expectations of behavior — what’s allowed and what’s not,” said lead author Ash Levitt of the University of Buffalo Research Institute on Addictions. “When there are two parents, it’s also easier to set rules and monitor how they’re being followed.”

Dr. Sharon Levy, Director of the Adolescent Substance Abuse Program at Boston Children’s Hospital, told the newspaper that supervision is likely more critical than family structure when it comes to teen drinking.