American liberals have led the campaign to reduce child poverty since Franklin Roosevelt, and it’s a proud legacy. But we have long had a blind spot.

We are often reluctant to acknowledge one of the significant drivers of child poverty — the widespread breakdown of family — for fear that to do so would be patronizing or racist. It’s an issue largely for working-class whites, Blacks and Hispanics, albeit most prevalent among African Americans. But just as you can’t have a serious conversation about poverty without discussing race, you also can’t engage unless you consider single-parent households. After all:

Families headed by single mothers are five times as likely to live in poverty as married-couple families.

Children in single-mother homes are less likely to graduate from high school or earn a college degree. They are more likely to become single parents themselves, perpetuating the cycle.

Almost 30 percent of American children now live with a single parent or with no parent at all. One reason for the sensitivities is large racial disparities: Single parenting is less common in white and Asian households, but only 38 percent of Black children live with married parents.

“The data present some uncomfortable realities,” writes Melissa S. Kearney, an economist at the University of Maryland, in an important book on this topic to be published next week. “Two-parent families are beneficial for children,” she adds. “Places that have more two-parent families have higher rates of upward mobility. Not talking about these facts is counterproductive.”

We liberals often perceive the world through prisms of privilege, but we rarely discuss one of the most important privileges of all — and it’s the title of Kearney’s book, “The Two-Parent Privilege.”

Let me interrupt this column with a shower of caveats. Many children raised in part by single moms do extraordinarily well; one was a two-term president in the 1990s and another served two terms until 2017. And I think the big driver for the rise in single-parent households is bad decisions by policymakers that led to mass incarceration and a collapse of earnings for working-class men.

Yet this is still so wrenching to discuss.

That goes back to 1965, when Daniel Patrick Moynihan wrote a prescient report about the decline of marriage among Black Americans. Moynihan, who himself had been raised mostly in poverty by a single mother, warned that family breakdown would exacerbate social problems, but he was denounced by liberals for racism and victim-blaming.

Scholars ran for cover. It helped greatly that the eminent African American sociologist William Julius Wilson of Harvard later conducted research in this area and praised Moynihan’s work as “prophetic.” But even today there is a deep discomfort in liberal circles about acknowledging these realities.

A scholarly organization in the field published a call in 2021 to “dismantle family privilege” (such as championing two-parent families), which it warned was embedded in “white supremacist society.” And while 91 percent of college-educated conservatives agree that “children are better off if they have married parents,” only 30 percent of college-educated liberals agree, according to a report to be released next week by the Institute for Family Studies.

In fact, children simply do better on average in school and typically earn more in adulthood if they have married parents, and this is particularly true of boys. It doesn’t seem to matter if the two parents are a mom and dad or a same-sex couple.

One advantage of a two-parent family is simply a function of arithmetic: Two parents can earn two incomes, meaning less poverty. Two-parent households seem to benefit not just their own kids but the neighborhood as well. Harvard’s Opportunity Insights group found that upward mobility was more likely for Black boys in neighborhoods with a higher share of Black dads living with their children.

One stunning and depressing gauge of racial inequity in the United States: The study found that 62 percent of white children live in low-poverty areas with fathers present in most homes, while only 4 percent of Black children do.

The collapse of marriage has happened mostly among less-educated Americans, including those who are white, Black or Hispanic. While many college graduates in theory embrace all kinds of family relationships, they remain traditional in their personal behaviors, mostly having children after marriage and raising their own kids in two-parent households. Brad Wilcox, a sociologist and family expert at the University of Virginia, calls this “talk left, walk right.”

The United States is an outlier in family breakdown. A Pew study of 130 countries found that American children were more likely to live with a single parent than those of any other nation. Conservatives sometimes argue that increases in welfare benefits undermined marriage, but this appears not to be a major factor — partly because European countries have both stronger social welfare programs and more two-parent families.

The proposed solutions from conservatives, such as marriage promotion efforts tried under the George W. Bush administration, likewise have had little impact. What does appear to strengthen marriage is lifting earnings of low-education men. This makes them more “marriageable,” researchers find. Lifting earnings is where liberals have the solutions: strengthened labor unions, community college support, skills training initiatives such as high school career academies and groups that provide technical training like Per Scholas.

The breakdown of family primarily among low-income Americans may be uncomfortable to talk about, but it is part of the apparatus of inequality in the United States. It doesn’t help when we avert our eyes, ignore the data and deny the existence of two-parent privilege.