It all started when Lenore Skenazy let her 9-year-old ride the subway home alone. She gave him a map, a MetroCard, a $20 bill and — just in case — some quarters for a pay phone call, and left him in the handbag section in New York’s original Bloomingdale’s. It was all his idea. He had begged Skenazy to just leave him somewhere and let him find his way back all by himself, until finally, on a spring day in 2008, she let him do it.

“I trusted him to figure out that he should take the Lexington Avenue subway down, and the 34th Street crosstown bus home,” she wrote in her 2008 column for the New York Sun, the one that ended up starting a movement. “If he couldn’t do that, I trusted him to ask a stranger. And then I even trusted that stranger not to think, ‘Gee, I was about to catch my train home, but now I think I’ll abduct this adorable child instead.’

“Long story short: My son got home, ecstatic with independence.”

Within days, Skenazy’s story went viral, as parents across the country wondered whether she was “America’s Worst Mom” or just one who valued her kid’s independence. Within a year, she wrote a book. She coined a new term. She called her parenting style “free-range,” in which she allowed her son to do various activities without her stifling supervision.

And now it’s the basis of a new law in Utah.

Gov. Gary R. Herbert, R, signed the “free-range parenting” bill into law earlier this month after it passed unanimously in both chambers of Utah’s legislature. It’s believed to be the first such law in the United States, according to Skenazy.

The measure, sponsored by Utah state Sen. Lincoln Fillmore, R-South Jordan, exempts from the definition of child neglect various activities children can do without supervision, permitting “a child, whose basic needs are met and who is of sufficient age and maturity to avoid harm or unreasonable risk of harm, to engage in independent activities.”

Those activities include letting children “walk, run or bike to and from school, travel to commercial or recreational facilities, play outside and remain at home unattended.” The law does not say what the “sufficient age” is.

Under the law, state child-welfare authorities can no longer take the children away from their parents if their kids are caught doing those various activities alone, as long as their kids are adequately fed, clothed and cared for.

“As a society, we’ve kind of erred, as our pendulum has swung for children’s safety, a little bit too much to the side of helicopter parenting, right?” Fillmore told FOX 13 earlier this year, while the bill was in committee. “We want kids to be able to learn how to navigate the world so when they’re adults they’re fully prepared to handle things on their own.”

State officials and lawmakers had said Utah was not in the business anyway of arresting parents for letting their kids walk around the neighborhood alone — but lawmakers were driven to pass the law after hearing of such cases in other states.

The law would conceivably have protected parents like Danielle and Alexander Meitiv, who were charged with child neglect twice in 2015 for letting their kids — ages 10 and 6 — walk home by themselves from a nearby Silver Spring, Md., park. In both cases, police picked the kids up, Child Protective Services was notified and an investigation was quickly opened. In both cases, they were cleared.

They too called themselves “free-range parents” in interviews with The Washington Post.

“The world is actually even safer than when I was a child,” Danielle Meitiv said at the time, “and I just want to give them the same freedom and independence that I had — basically an old-fashioned childhood. I think it’s absolutely critical for their development — to learn responsibility, to experience the world, to gain confidence and competency.”

Critics, of course, have argued that the “free-range parenting” style is not safest for children, despite the fact that stranger abduction is rare. A bill similar to the one that passed in Utah was proposed in the Arkansas legislature last year, but died in a House committee, overshadowed by fears of child abduction.

Skenazy, who blogs regularly for Reason magazine, responded with a sharply worded blog post:

“And so Arkansas has preserved the right of its authorities to barge in on families who simply want their kids to have a tiny taste of independence most of us remember from our own childhoods,” she wrote for Reason. “Why give kids freedom — why give parents freedom — when you can take it away so easily and say you’re championing safety in the process?”