> > It's legal for someone under 21 to drink alcohol, but only in beverages/food with very small quantities. For instance, you could buy non-alcoholic beer, even though it has from around 0.1 to 0.73 percent alcohol.
> Really? Where did you find this? I'm not challenging you, but now I'm curious.
> > In contrast, in private residence you can drink whatever your parents give you.
> This too.
> Ell"always curious, it seems"myruh

Most national laws about underage drinking were set in stone with the "National minumim drinkage age act" of 1984. It says that it is illegal for anyone under 21 to purchase or have public possession of alcoholic beverages.
You can find details about that here:
http://www.mudpc.org/laws.html

The definition of beer, and I believe alcoholic beverages in general, is any drink with more than 0.5% alcohol content.
You can find the definition of beer under section 25.11 here:
http://www.atf.treas.gov/regulations/27cfr25.htm

and the percent alcohol of different beverages here:
http://brewery.org/brewery/library/AlClbinger.html

So, although there exist "non-alcoholic" beers at .73%, they should be considered beer. But anyone could legally purchase a beverage at 0.49% alcohol.

As for the family being allowed to let their child drink in private, that's allowed because the "National minimum age act" prohibited public possession, not private. I think, but I'm not sure, that drinking alcohol has always been fine -- it's the possession where they get you.

And a final comment. The national laws were pushed upon states with promise of penalty if they did not comply. The laws can change from state to state if a state chose not to comply (most states complied) or went more extreme than the national laws required.

Eu'alcohol is my hobby'gene