It’s one of the seemingly ironclad rules of adolescence: In the United States, you can’t drink legally until you’re 21. Of course, our underage consumption laws are flouted regularly. More than half of American 20-year-olds have tried alcohol at some point in their lives, according to the most recent numbers from the National Survey on Drug Use and Health.

But as it turns out, not all of that underage drinking is, strictly speaking, illegal: At least 37 states have some sort of exception in their drinking laws that allow underage people to drink at home and within the company of family members. According to the National Institute on Alcohol Abuse and Alcoholism, the patchwork of state laws governing exceptions to statutes on underage alcohol possession may look simple at first on a map, but it masks incredible complexity in underage drinking exceptions. Some states make exceptions for when minors may consume alcohol. Others make exceptions for when they may possess it. Still other states, like Arkansas, have no exceptions for underage possession or consumption but nonetheless make exceptions for parents who want to provide alcohol to their children. It all adds up to a confusing mess that can be next to impossible for parents, teens and even legal professionals to understand.

“It’s perplexing — what do we tell parents?” said David J. Hanson, an emeritus professor of sociology at SUNY Potsdam, in an interview. Hanson has studied alcohol policies for more than 40 years, and he says that sometimes self-contradictory underage drinking regulations make for confusion and “legal mischief.”

I asked Hanson what he thought about the legal situation in Arkansas, where the law simultaneously says that minors are prohibited from possessing alcohol in all circumstances but that parents are nonetheless permitted to give alcohol to their children. If a parent gives a drink to a child, does that mean that the child is breaking the law but the parent isn’t?

“I simply don’t know,” Hanson said. “And that is I think one of the fundamental problems. We’re of normal intelligence and we can’t figure out what the law is. That is a serious problem.”

It’s not just regular people who have a hard time making sense of these apparent contradictions — some states even give out seemingly conflicting information about their underage statutes. If you search for underage drinking laws in New York, for instance, you’ll find this pamphlet from the State Liquor Authority that states, rather unequivocally, that “if you’re under 21 years old, it is a violation of the law to possess alcohol with the intent to consume.”

But New York’s actual underage drinking statute makes an explicit exception for drinking with parents: “A person under the age of 21 years may possess any alcoholic beverage with intent to consume if the alcoholic beverage is given … to the person under 21 years of age by that person’s parent or guardian.”

Bill Crowley, a spokesperson for the State Liquor Authority, points out that they’re primarily concerned with what happens in the bars, restaurants and stores that they license — not with what may happen in people’s homes. So if a parent tried to buy a drink for their kid in a bar, that would be a citeable offense.

Could the waters get any muddier? Of course they could. Besides exceptions for parental consent or drinking at home, there are many other legal carve-outs. According to the nonprofit nonpartisan site procon.org, 26 states allow minors to drink as part of religious services. Another 16 allow minors to consume alcohol for “medical” purposes, although these provisions are likely intended to protect the use of alcohol-containing medicines like cough syrup. Students in culinary school can drink for educational purposes in 11 states, and people under 21 can legally drink as part of government research or police work in four states — for instance, to go undercover and have a drink with a suspect at a bar.

Hanson, the sociologist, says these muddled laws reflect muddled attitudes toward alcohol consumption in the United States. “All these conflicting laws result from a cultural ambiguity — basically they reflect the fact that we as a society don’t really agree on how to deal with alcohol.”

The story of American drinking is a complicated one. As with many other vices, alcohol is simultaneously celebrated — “It’s Miller time!” — and condemned in popular culture. More than 1 in 7 U.S. adults say drinking alcohol is a sin, according to a 2015 Pew Research Center survey.

All this ambiguity, and the legal confusion it creates, might have real-world consequences, too. If people don’t understand what the laws say, they don’t know whether they’re being broken. “I suspect many people are being convicted for crimes they didn’t commit because of the confusion,” Hanson says.

For Teens

Illegal Possession

It is a civil violation* for any person under the age of 21 to possess liquor or imitation liquor except if it is within the scope of their employment or in their home in the presence of their parent. Fines for illegal possession are as follows:

First offense: $200 to $400

Second offense: $300 to $600

Third or subsequent offenses: $600

* Youths 17 years or younger are charged with the juvenile crime of illegal possession.

Illegal Transportation of Liquor

No person under the age of 21 shall transport alcoholic beverages in a motor vehicle except in the scope of their employment or at the request of their parent. The penalties for illegal transportation are:

First offense: 30 day license suspension and a fine of no more than $500;

Second offense: 90 day license suspension and a fine of not less than $200; and

Third offense: One year license suspension and a fine of not less than $400.

Note: You cannot be charged for both possession and transportation for the same violation. Law enforcement must charge for transportation when a minor is caught driving with alcohol in the motor vehicle.

The Teen OUI Law (Zero Tolerance)

Any motor vehicle operator under 21 who operates or attempts to operate a motor vehicle with any alcohol in their blood* shall have their license suspended by the Secretary of State for one year. If they have a passenger under 21, an additional 180-day suspension will be imposed. Refusal to be tested will result in suspension of their operator’s license for at least 18 months.

* Minors who test .08 percent or more will be prosecuted with the criminal offense of Operating Under the Influence, which results in even greater consequences.

For Parents

Furnishing Liquor or Imitation Liquor to a Minor

It is a criminal offense for any person, adult or minor, to furnish liquor or imitation liquor to a minor, or allow a minor under that person’s control, or in any place under that person’s control, to possess or consume liquor or imitation liquor. This offense may result in fines from $500 to $2,000 and/or a jail sentence for up to 12 months. If an injury or death occurs, the person responsible for furnishing the alcohol may be charged with a felony and could be sued under the Maine Liquor Liability Act.

Maine Liquor Liability Act

The Maine Liquor Liability Act provides a way to pay for the cost of damages that result from alcohol-related incidents. Anyone who sells, gives, or otherwise provides liquor to an individual, whether they hold a Maine Liquor License or not, can be sued for negligent or reckless conduct under this lay.

Negligent conduct is defined as service liquor to someone you know is a minor or intoxicated as defined by law.

Reckless conduct is the intentional serving of liquor to a minor or a visibly intoxicated person when the server knows and conscieously disregards an obvious and substantial risk that serving liquor to that person will cause physical harm to the drinker or to others.

Financial Implications

Repayment may be awarded for property damage, bodily injury, or death caused by the consumption of liquor served by the defendant. The limit on awards is $250,000 plus limitless medical expenses.

If you are sued as a result of providing alcohol to a minor or visibly intoxicated person, which is a violation of the law, your homeowner’s insurance will not protect you.

Allowing minors other than your own children to drink alcohol in your home (even if you do not supply the alcohol) is a criminal offense, which may result in fines or even jail sentencing.