It's estimated that more than 10.5 million teenagers in the U.S. drink. And a new survey of underage drinkers finds that many of them are getting booze from adults, including their parents.

Acting Surgeon General Steven Galson said too many parents are serving as enablers.

Just over half of the 158,000 teens surveyed from 2002 to 2006 had consumed alcohol, and 40 percent of those who admitted to drinking say an adult they know hooked them up for free.

The most common place for teens to drink is someone else's house, though plenty admit to having last had a drink under their own roof. And the survey suggests that while girls start drinking before boys, eventually the boys catch up and surpass them as they near the legal drinking age.

About one in five admitted binge drinking: that's five or more drinks at a time.