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, 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.