Several years ago economist Walter Williams explained “How Not to Be Poor”:

Avoiding long-term poverty is not rocket science. First, graduate from high school. Second, get married before you have children, and stay married. Third, work at any kind of job, even one that starts out paying the minimum wage. And, finally, avoid engaging in criminal behavior.

Williams is right—it’s not rocket science. Yet many Americans are shocked to discover that life choices are often (though certainly not always) the most determinative factor in the financial security of both individuals and families. Some people, particularly on the political and cultural left, are even offended by the idea that promotion of bourgeois institutions like marriage might be the key to entering—and staying in—the middle class.

But the evidence has e so hard to ignore that even the New York Times is being forced to acknowledge the obvious. This weekend, Jason DeParle wrote a lengthy article highlighting how a primary cause of class division in this country is based on who gets—and stays—married:

Estimates vary widely, but scholars have said that changes in marriage patterns — as opposed to changes in individual earnings — may account for as much as 40 percent of the growth in certain measures of inequality. Long a nation of economic extremes, the United States is also ing a society of family haves and family have-nots, with marriage and its rewards evermore confined to the fortunate classes.

“It is the privileged Americans who are marrying, and marrying helps them stay privileged,” said Andrew Cherlin, a sociologist at Johns Hopkins University.

About 41 percent of births in the United States occur outside marriage, up sharply from 17 percent three decades ago. But equally sharp are the educational divides, according to an analysis by Child Trends, a Washington research group. Less than 10 percent of the births to college-educated women occur outside marriage, while for women with high school degrees or less the figure is nearly 60 percent.

Long concentrated among minorities, motherhood outside marriage now varies by class about as much as it does by race. It is growing fastest in the lower reaches of the white middle class — among women like Ms. Schairer who have some postsecondary schooling but no four-year degree.

While many children of single mothers flourish (two of the last three presidents had mothers who were single during part of their childhood), a large body of research shows that they are more likely than similar children with married parents to experience childhood poverty, act up in class, e teenage parents and drop out of school.

In other words, being the child of a single mother means that you are likely to do the opposite of what will keep you out of poverty.

Unfortunately, society is now much less concerned about the future of these children than we are about not hurting the feelings of single mothers. We’re often told that we should not judge single moms because we do not know their circumstances—and to some extent that is true.

But while we do not want to return to the days when single mothers are demonized, we also need to stop treating them as if they are morally and intellectually incapacitated. Single mothers must be treated with the same dignity owed to all adults, which requires holding them responsible for their choices and actions.

Having been raised by a single mom, I understand and empathize with the hardships of being an unmarried parent. But I also recognize that many of the choices my own mother made (e.g., romantic attachments to men who were morally and financially unreliable) were the reason we lived in poverty for most of my childhood.

Such destructive personal choices often lead to negative es for one’s children, as some of the women in the Times‘ story are finding:

Ms. Schairer has trouble explaining, even to herself, why she stayed so long with a man who she said earned little, berated her often and did no parenting. They lived with family (his and hers) and worked off and on while she hoped things would change. “I wanted him to love me,” she said. She was 25 when the breakup made it official: she was raising three children on her own.

Single mothers, however, are only half—and often the more visible half—of the problem with broken families. Absent and negligent fathers, especially those who are able but unwilling to support their children, should bear the brunt of society’s ire.

Too many men today believe their role as parents is optional or contingent on their ability to live the lifestyle they want. If they move on to a second marriage, they believe their duty is to expend their financial and emotional resources on their new family. This “second es first” principle has e the accepted norm in a culture that is willing to be satisfied that some kids, any kids, are being taken care of by a father in the home. If a man won’t provide for all his children, says society, the least we can do is be grateful he is caring for his latest brood.

But that’s not good enough. And neither are discussions about e inequality” that present charts and graphs about economic activity but fail to acknowledge the underlying pathologies that are widening the earnings gap. The economic problems of America are primarily the price we pay for our social problems. Unless we begin to treat economic and social issues as a whole, rather than as nonoverlaping magisteria, we’re going to continue to be a nation that incentivizes the creation of a an underclass.