It’s getting harder for parents to raise financially independent young adults.

Many banks refuse to open individual checking accounts for 16- and 17-year-olds, requiring parents to jointly own the account, even if the youngsters have a job. Colleges urge parents to link their bank accounts or credit cards to the prepaid cash cards that double as their students’ ID cards, to ensure a regular flow of funds from the Bank of Mom and Dad.

And under the new credit-card law that goes into effect early next year—part of a broader move toward aggressive consumer protection—parents of those under 21 will have to agree to take responsibility for their kids’ credit cards unless the young applicants can show they have the income to qualify.

All of this seems to encourage parents to interfere with—and maybe even bail out—these young adults. And it comes at an age when the youngsters themselves should be taking on personal responsibility and making their own financial decisions.

So this is the kind of mean and rotten parent I’ve become: Recently, I vigorously persuaded my 19-year-old daughter to get her first credit card.

Most young people should consider getting a credit card in college because they will need a credit record to lease an apartment, land a car loan, qualify for a good rate on car insurance and maybe even get a job. My daughter wanted to wait until next year to get a card, but I would have had to cosign for it—something I was unwilling to do, even though she’s very conscientious.

The reason? I believe youngsters need room to make their own mistakes—and learn from them when the consequences (and dollar amounts) are low. It’s a parenting theory I learned from Jim Fay, co-founder of Love & Logic Institute Inc. in Golden, Colo. Since the late 1970s, he has warned about the wrong messages sent by helicopter parents, who swoop in to rescue their kids, and drill sergeants, who tell their children what to do step by step.

If my daughter pays her bills late in college, she will learn quickly about late fees and the impact on her credit score. But if I’m on the account, I’ll have to choose between her life lesson and my own credit score.

Cosigning on a credit-card account, as Mr. Fay notes, “is a good way to end up paying the bill.”

The new credit-card law will also limit the marketing of card offers to young people, apparently in response to reports that they were running up huge debts. Those same reports prompted Soyeon Shim, a University of Arizona professor specializing in consumer behavior, to survey more than 2,000 freshmen at the school, the first in a longitudinal study funded by the National Endowment for Financial Education.

The survey, published in April, found that 58% of the students had a credit card and an average debt of $169. Generally, they weren’t spendthrifts: More than 60% of those with credit cards said they used them a few times a month or less and paid the bill in full every month.

But what jumped out at the researchers was that more than 70% of the students reported a “financially risky” behavior—in other words, they had made a mistake—in the past six months, by, for instance, not paying a bill on time, maxing out a credit card or taking out a payday loan.

Dr. Shim notes that the percentage of students reporting a risky behavior was the same for those with credit cards as those without. In other words, it wasn’t credit cards that got them into trouble, but other factors.

And what was the greatest influence on the students’ behavior? Overwhelmingly, it was their parents. What students learned at home was far more important than what they learned from having jobs or in financial-literacy classes. Students who reported good communication with their parents about money also felt like they had more financial knowledge and more control over their finances, which Dr. Shim believes may lead to greater financial happiness when they are adults.

So what’s a parent to do?

Start early. Most banks and credit unions will provide fee-free savings accounts to kids. Grade-school children can understand budgeting basics. Young teens can begin to learn about how credit works. Share the ways you use a credit card and how you pay it off.

Encourage independence. Let kids decide how they spend their allowance or earnings. Some banks, like Wells Fargo, will let you open a joint checking account for kids as young as 13. Some credit unions and banks, like Bank of America, will open an individual checking account for those 16 or 17. If you’re in a joint checking account, resist the urge to monitor it online; instead, talk with your teen about budgeting and spending.

Pick plastic wisely. If you want your young teens to learn about using cards—or they need to have a card to go on a trip—consider a prepaid card, which works much like a reloadable gift card. Most cards are pricey, with monthly fees, transaction fees or charges to deposit money, so be sure to compare offers carefully.

You can make your older teens authorized users on your credit card, which can help them build a credit record. But first explain your expectations and rules about when they can use it. And when it’s time for those young adults to get their own cards, go through the fine print together to understand credit limits, interest rates, due dates, cash advances and the many different ways to amass penalty charges.