PORTLAND — Teens and alcohol use: It’s a tough subject.

Parents of adolescents know they have to balance their child’s growing need for independence with the need to keep them safe.

And alcohol is an issue that parents of teens constantly deal with: Our culture is saturated with messages that imply underage alcohol use is cool, sexy, fun, and most of all, normal.

But it’s not the norm. Despite popular misconception, fewer than half of all high school seniors in Portland — and only about one-third of all high school students in the city — have had alcohol in the past 30 days (2009 Maine Integrated Youth Health Survey).

For those youth who do drink, it’s a risky proposition, and taking away the keys doesn’t change that.

Only one-third of teen alcohol-related deaths are from vehicle crashes; the other two-thirds are from injuries that can happen far away from an automobile: slips, falls, drownings, burns, poisonings, homicides and suicides, according to a 2004 analysis.

Still, parents want what’s best for their kids, and it might seem like hosting and chaperoning teen drinking parties is the best way to prepare them for the drinking that can occur when young adults leave home.

Unfortunately, this is illegal and can actually backfire.

A 2009 study in Addictive Behaviors found that kids whose parents let them drink in late high school are likely to drink more heavily in college and experience more negative consequences related to drinking (such as assaults, property damage, unwanted sexual contact, academic failure, etc.).

Furthermore, a 2004 study in Journal of Adolescent Health found that when a parent or friend’s parent provides alcohol for underage drinking parties, youth are far more likely to drink and to engage in binge drinking.

As for allowing teens to drink at home with their own parents (for example, a few sips with dinner) there is mixed evidence regarding whether this is beneficial or harmful. This is a decision that Maine law leaves to the discretion of each family, and rightly so.

What the research does clearly show is that kids are highly vulnerable to addiction and future alcohol problems if alcohol is introduced during the teenage years.

Here’s why: Adolescent brains just aren’t completely mature. The frontal lobe — the part of the brain that controls planning, reasoning and impulse control — continues significant development through the mid-20s, according to a 2006 article in Psychological Science in the Public Interest.

Adding alcohol to developing decision-making skills puts kids at higher risk for unintentional injuries, unwanted sexual contact, pregnancy, sexually transmitted infection, academic problems, depression, suicide and other substance abuse.

The best way for parents to keep kids from alcohol-related problems is by keeping firm expectations and loving communication.

Parents can also role-model healthy alcohol consumption, and talk about how media portrays alcohol use.

We suggest signing a family contract with your teen so that rules and consequences are completely clear — a sample contract is available on our website at 21reasons.org/parents.php — and engaging in frequent communication to maintain a trusting relationship.

But does it work? According to a statewide survey, it does. Maine students who report that their parents think that it is wrong for them to drink are one-third as likely to have had alcohol in the past 30 days (2008 Maine Youth Drug and Alcohol Use Survey).

It can be hard for parents to talk to their kids about drinking. It’s even harder to take an unpopular stance. But sometimes parents know that they have to do an unpopular thing for the safety of their kids.