In early 2014, Harry Levant, a successful Philadelphia lawyer, was in an Atlantic City casino hotel room about to take his own life. Over the previous two years, he had stolen $1.9 million, mostly settlement claims he had won for his clients. Now, the money was gone — frittered away to feed his gambling addiction. Mr. Levant, desperate and broke, felt he had nothing to live for.

“I came within seconds of taking my own life,” he told us. Instead, he thought of his children, vowed to change, and called a gambling addiction helpline. He was disbarred, sentenced to eight years’ probation and ordered to repay his victims. He now works as a gambling addiction therapist. “Gambling addiction took my brain, my heart, my soul, my conscience,” he said.

Mr. Levant can remember precisely his very first bet: He won $12 on a football game between the Houston Oilers and the Washington Redskins. He was just 15 years old.

That’s not unique. As sports betting has spread across the United States — supercharged by a 2018 Supreme Court decision that allowed states to legalize it and set their own rules — more and more teenagers, especially boys, are being drawn into a heady world of gambling, almost exclusively via smartphone apps. Most states limit gambling to those at least 21 years old, with a few states allowing it at 18. But younger teens find easy workarounds, betting through older siblings or friends, or using fake documents to verify their age online.

One widely circulated survey by the National Council on Problem Gambling found that between 60% and 80% of high school students had reported gambling for money in the previous year, and as many as 6% of them were considered to have a problem with gambling.

For decades, professional sports considered gambling taboo. But now, with 38 states and D.C. allowing legal betting on games, the ubiquity of sports betting advertisements, and lucrative tie-ups between professional teams and gambling companies, a generation of young people has grown up with gambling as a normal — even integral — part of spectator sports, one which, according to the impression that ads create, is an easy money, no-lose proposition.

A growing body of research — in the United States, and in countries such as Australia and Britain with longer histories of legal sports betting — shows a strong correlation between early youth gambling and problem gambling later in life.

Young people might be more susceptible to gambling addiction because their still-developing brains cannot deal with the adrenaline rush of placing a bet and awaiting the outcome.

Many online games offer add-on features such as “loot boxes” containing items of uncertain value that can be purchased for real money. Preliminary research has found a link between spending money for loot boxes and problem gambling, but some question whether there’s a direct causation. Loot boxes have been the subject of several mostly unsuccessful court suits and regulatory action in the United States and elsewhere.

Concern over youth gambling has prompted several states to take action. Virginia’s legislature two years ago overwhelmingly passed legislation, signed by Gov. Glenn Youngkin, to introduce gambling awareness into the state’s school curriculum. Similar efforts in other states, including Maryland, have failed, often because of opposition from educators and teachers’ unions that welcome the tax revenue generated from legal sports betting.

Congress should immediately pass the Kids Online Safety Act, or KOSA, which passed the Senate 91-3 but has stalled in the House. KOSA would prevent social media platforms from advertising harmful products, including gambling, to children, restrict use of personalized algorithmic recommendation to kids and hold online game makers responsible for their products under a “duty of care.”

Legislation, state or federal, is no substitute for parental responsibility, however. Most parents wouldn’t let a child try cigarettes or alcohol or cigarettes. Why let them place a bet with a sportsbook?