Few political debates in this country are as freighted with emotional, cultural, and ideological baggage as those that touch on the choices people make in forming families. When public discourse turns to decisions about wedlock and child-rearing – think of Daniel Patrick Moynihan’s 1965 report on “the breakdown of the Negro family,” or the uproar over Murphy Brown during the 1992 presidential race, or the modern push for same-sex marriage – civility is too often swept away amid a storm of hurt feelings and self-righteousness.

All the more reason, then, to welcome two recent studies – one national in scope, one focused on Massachusetts – on the effects of single parenthood and the decline in marriage. Both lay out the data with clarity, while avoiding moralizing or disapproval.

One report, aptly titled “For Richer, For Poorer,” is by sociologist W. Bradford Wilcox of the American Enterprise Institute and economist Robert I. Lerman of the Urban Institute. It documents the profound links that connect family structure and financial well-being, and underscores what decades of empirical data have shown: Families headed by married couples tend to be much stronger economically than those headed by unwed single parents.

“Anyone concerned about family inequality, men’s declining labor-force participation, and the vitality of the American dream should worry about the nation’s retreat from marriage,” the authors write. The steady fall in the percentage of married two-parent households – from 78 percent in 1980 to 66 percent in 2012 – goes a long way toward explaining why so many ordinary families have trouble climbing beyond the lower rungs on the economic ladder. Correlation isn’t proof of causation, of course. But there is no refuting the strong association between growing up with both parents in an intact family and achieving higher levels of education, work, and income as young adults.

Wilcox and Lerman put dollar amounts to the “intact-family premium” reaped by those who are raised by their own biological or adoptive parents. By age 28 to 30, for example, men from such backgrounds are earning on average $6,500 more per year in personal income than their peers from single-parent homes. And since growing up with both parents increases one’s likelihood of marrying as an adult, men and women who were raised by married parents tend to enjoy much higher family incomes as well – in the case of that 28- to 30-year-old male, more than $16,000 higher, on average. (Among all married adults who were raised in a two-parent home, the annual average “family premium” is higher still: $42,000 more when compared to their counterparts from single-parent families.)

To be sure, not all families headed by married parents are stable or successful, and not all children raised by single parents struggle economically or professionally. Barack Obama, who was two years old when he was abandoned by his father, is dramatic evidence of that.

But as Obama himself says, the data aren’t in question. “Children who grow up without a father are more likely to live in poverty. They’re more likely to drop out of school. They’re more likely to wind up in prison. They’re more likely to abuse drugs and alcohol.”

As the second study documents, these unhappy trends haven’t bypassed Massachusetts.

In recent decades, the fraction of Bay State children in single-parent homes has risen to more than one in three. While the state’s marriage rate has plummeted – there were 49,000 Bay State marriages in 1980 vs. fewer than 36,000 in 2011 – the rate of out-of-wedlock births has soared. The Massachusetts Family Institute, in a report replete with just-the-facts-ma'am statistics, lays out the economic and social costs.

“The increase in fatherless families is a significant contributor to income inequality,” it notes. In 2013, the median Massachusetts income for married-couple households with children was $114,376. For households headed by single mothers, it was just $26,999. Citing data from the National Survey of Children’s Health, the report observes that only 6 percent of children in married-couple homes have no parent who works full-time. For kids being raised by never-married single mothers, the comparable figure is 46 percent.

There is no finger-wagging or blame in these reports, just the numbers – and compassion. The child poverty rate is so much steeper in single-parent homes than in two-parent homes, and it is heartbreaking that so many young people raised in fatherless families will have such trouble climbing out of poverty as they grow older.

Income inequality may or may not be “the defining challenge of our time,” as Obama and others have proclaimed. But the most significant driver of that inequality – the biggest impediment to upward economic mobility – isn’t hard to identify. The higher the fraction of children not being raised by their married parents, the more of our fellow citizens for whom the American Dream is likely to remain beyond reach.

Jeff Jacoby is a columnist for The Boston Globe.