Our biggest menace is demise of the two-parent family

A specter is haunting America — gradually, almost imperceptibly undermining our environment in ways that imperil our children's futures.

From Japan to Sweden, other nations understand this danger, and have done far better against it. On this, America is in last place in the developed world.

Scientists have warned us about the threat for nearly half a century. By the most modest scholarly estimate, a 2008 study by economist Benjamin Scafidi, this menace costs our nation more than $306 million each day, costs borne disproportionately by the most vulnerable Americans.

Yet one of the two major political parties, aided by industry and parts of the academy, denies that there is any threat at all, ignoring dozens of studies by scholars at Princeton, Columbia and the Brookings Institution.

If there was ever a war on science, this is it.

This existential danger, even scarier than climate change, is family change.

The breakdown of the American two-parent family over the past half-century has been more rapid and unprecedented than that of Greenland's ice sheet, with even worse consequences.

Combined with the rise of divorce, that means that roughly one in four American children now lives in a single-parent home, more than twice the percentage in supposedly libertine nations like Sweden and France. About a third of American children live apart from their fathers.

That might not be a problem, save for the numerous studies finding that on psychological, educational and economic indicators, kids do far better with two parents than one. Abuse of all kinds is less common for married couples than for cohabiting or single parents.

As the Brookings Institution's Ron Haskins and Isabel Sawhill point out, if today's family structure were the same as in 1970, the poverty rate would be roughly one-quarter lower.

Penn State Prof. Molly Martin estimates that 41 percent of the increased economic inequality from 1976 to 2000 could be explained by family changes concentrated among the poor and near poor. By and large, the college-educated still get married before having kids, and they stay married afterward. That gives their kids a huge leg up in life.

In his powerful autobiography, "Dreams from my Father," Barack Obama expressed the pain of growing up without a father, in a loving yet unstable family environment. To his credit, Obama resolved to do better, and his own marriage and fatherhood make a worthy example.

To paraphrase New York University Prof. Jonathan Haidt, it is time for Republicans to admit that marriage is good for gays and lesbians, and long past time for Democrats to admit that marriage is good for everyone else, especially children.