About half of U.S. youths under age 21 have consumed alcohol, and of these 40 percent said that they got their drinks for free from an adult during the past month, a new survey finds.

The Associated Press reported June 26 that federal researchers surveyed teens between 2002 and 2006 and found that about one in four got their alcohol from an unrelated adult, about 6 percent got alcohol from a parent or guardian, and about 8 percent received their drinks from another adult family member. About 4 percent of those surveyed said they took alcohol from their own home.

''In far too many instances parents directly enable their children's underage drinking -- in essence encouraging them to risk their health and well-being," said acting Surgeon General Steven K. Galson. ''Proper parental guidance alone may not be the complete solution to this devastating public-health problem -- but it is a critical part."

The survey from the Substance Abuse and Mental Health Services Administration also found that about 20 percent of underage drinkers ages 12-20 had engaged in binge drinking during the past month. About half of those surveyed said they drank in someone else's home, while 30 percent said they were in their own home and 9.4 percent said they had their last drink in a restaurant, bar or club.

Girls were somewhat more likely to drink at a younger age than boys, but this was reversed as they got older.