More than $22 billion -- that's how much researchers estimate underage drinkers spent on alcohol products in 2001. That's almost as much as was spent by alcohol-dependent adults -- $26 billion. And together, these two groups of people (who according to law and convention shouldn't be drinking at all) account for more than a third of the alcohol industry's sales.

The findings, from work led by Susan E. Foster of the National Center on Addiction and Substance Abuse at Columbia University, make it pretty clear that the public health messages young people get about the dangers of drinking are no match for the societal forces that make it not just acceptable, but expected, for this age group to experiment with alcohol.

And they raise some very tough questions for parents of pre-teens and teens, especially those many millions of us who buy and consume alcohol ourselves. My husband and I never thought twice, when our kids were young, about drinking wine with dinner or having a couple of cocktails at a weekend party. But now, I can't help thinking about the "do as I say, not as I do" message that we're sending. Not that my parents' generation ever seemed to feel much angst over that -- "Because I said so" seemed like enough of a reason back then.

But alcoholism runs like a destructive thread through so many families, including my own, and no one wants to see their child wrestle with that.

And then there's the research that indicates one of the best ways to prevent alcohol dependence is to delay the age at which regular drinking begins. According to some research, people who begin drinking before age 15 are four times as likely to become dependent on alchohol as those who start after they turn 21.

Of course, that's another example of research that really doesn't do much to help set practical parenting guidelines. I can't help wondering if the kids who start drinking before age 15 aren't already predisposed to do so. So, is the early onset of drinking the cause of later dependence, or simply a symptom?

No way I can figure that out in my free time.

I gave up alcohol while I was pregnant. (But not caffeine. Got to draw the line on maternal sacrifice somewhere.) Should I give it up while my kids are teens? That's a long time to go without -- especially during what are billed as the highest-stress years of parenting. But it would be good for my health, no doubt. It's worth thinking about.