There are some nuances this article misses (and others that it gets), still, the big picture is sobering:
But for inequality more broadly, Mr. Western found that the growth in single parenthood in recent decades accounted for 15 percent to 25 percent of the widening income gaps. (Estimates depend on the time period, the income tiers and the definition of inequality.) Gary Burtless of the Brookings Institution found it to account for 21 percent. Robert Lerman of the Urban Institute, comparing lower-middle- and upper-middle-income families, found that single parenthood explained about 40 percent of inequality’s growth. “That’s not peanuts,” he said. . . .
Forty years ago, the top and middle income thirds had virtually identical family patterns: more than 95 percent of households with children in either tier had two parents in the home. Since then the groups have diverged, according to Mr. Western and Ms. Shollenberger: 88 percent at the top have two parents, but just 71 percent do in the middle.
“Things remained extremely stable in the top third,” Mr. Western said. “The middle is increasingly suffering some of the same disadvantages as the bottom.”