Nearly a quarter of the August 2011 London rioters were under 18 years old.

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When four days of London rioting in August 2011 left behind $480 million (£300 million) in damaged property, government officials didn't blame just the looters for wrecking so many cars and buildings. In the wake of that mayhem, in which roughly 20 percent of the rabble-rousers arrested were under 18 years old, Prime Minister David Cameron also called out the roving teens' parents for failing to raise up law-abiding youth [source: Quilty-Harper et al]. And rather than just verbally slapping those mostly low-income mums and dads on the wrist, Cameron and the Children's Ministry spearheaded an $8-million (£5-million) test program of government-subsidized parenting classes to cover topics such as nutrition, reading and discipline [source: Richardson].

As of May 2012, vouchers for free parenting classes had been released to the public, but the save-the-kids plan also made some Brits wary. The notion of applying careful methodologies and detailed instruction to parenting is an American-born import that floated across the pond in the 1970s [source: Gentleman]. In the United States, a growing emphasis on "good parenting" in the 20th century spawned an entire industry of experts, self-help books and products that are supposed to help men and women bring up blue ribbon babies. Some in the U.K. feared that the parenting classes represented an unnecessary injection of American angst and stress into the tough-enough duty of childcare [source: Gentleman].

But when did parenthood, a word coined not so long ago in the mid-1800s, become something that required instruction manuals in the U.S. or abroad? For Americans, that occurred as a domestic ripple effect of the Industrial Revolution, which also delayed the age people got married, diminished the national fertility rate and ushered nuclear families from the fields to more urbanized areas. Before that, large families were the norm, meaning that siblings had to help raise each other, picking up parenting basics along the way [source: Lepore]. By 1926, when the publisher of Child, the first American magazine intent on delivering parenting how-tos, recognized a maternal market waiting to be served, new mothers unversed in baby-handling were desperate for step-by-step instructions on how to be adequate, if not superior, parents [source: Lepore]. Since then, that collective yearning for child rearing know-how has only grown, prompting the question of whether the reams of parenting advice Americans have gobbled up in the ensuing decades have made a positive impact on the kids.