That these areas have a high minority population, particularly among blacks and Hispanics, is not a coincidence, said Ron Haskins, a senior fellow at the Brookings Institution.
"About 70 percent of black kids are born outside marriage, and then you have those born in a marriage, about half of them end in divorce," he said. "And first-generation Hispanics have a relatively low divorce rate … but once you get into the second generation that disappears."
Haskins said many factors contribute to the high concentration of single-parent households among those minority groups, but "the bottom line is I don’t think anyone really understands why."
Children who do grow up with one parent are more likely to repeat that pattern as adults, he said. But it doesn’t always start out that way — in fact, a recent study Haskins co-authored shows that most of those children are born into households with both parents present.