Lead researcher Barbara J. McMorris of the School of Nursing at the University of Minnesota says some parents allow their adolescent children to drink alcohol in small amounts on occasion if an adult is present -- thinking they will learn to drink responsibly if introduced to alcohol slowly in a controlled environment.
Other parents take more of a "zero tolerance" approach and forbid youth drinking under any circumstances. This less permissive approach is predominant in the United States, but many other countries have more supervised drinking.
McMorris and colleagues in Melbourne, Australia and the Social Development Research Group in Seattle surveyed more than 1,900 seventh-graders.
By eighth grade, about 67 percent of Australian youths had consumed alcohol with an adult present, while 35 percent of those in Washington state did.
However, by ninth grade, 36 percent of Australian teens, compared with 21 percent of U.S. teens, had experienced alcohol-related consequences, such as not being able to stop drinking, getting into fights or having blackouts.
The findings are published in the Journal of Studies on Alcohol and Drugs.