A number that comes up frequently when talking about African-American families is that 70 percent of births happen out-of-wedlock. The figure is frequently invoked, according to the Atlantic's Ta Nehisi Coates, as evidence of the declining morality of the black family. Consider this quote from Fox News contributor Bernie Goldberg on a recent edition of "The O'Reily Factor."

"In the entire recorded history of the planet, there has never been a greater voluntary abandonment of men from their children than there is today in black America. Never. I mean, when men went off to war, they had to go off to war. That wasn't voluntary. But never as great of voluntary abandonment of children by their fathers than in black America today."

Even the segments of the black community are prone to this kind of thinking, according to Coates. "Just as often you see it invoked by black people themselves in much the same way. What undergirds all of this is the sense that the black community of today is somehow deficient in a way that the black community of yesteryear was not," he wrote in a piece for the Atlantic.

But according to Coates a more interesting picture comes into focus by comparing the birth rates of married and unmarried black women.

Using Census data, Coates argues that "one obvious reason that you have a higher percentage of children born out-of-wedlock in the black community is that the number of unmarried women (mothers or not) has grown a lot, while number of married women has grown only a little."

Coates also uses Census data to show that while the number of unmarried black women has substantially grown, the actual birthrate (births per 1,000) for black women is at the lowest point it has ever been. "So while a larger number of black women are choosing not to marry, many of those women are also choosing not to bring kids into the world," said Coates.

The birthrate for unmarried black women is mirrored by an even steeper drop among married black women. "Whereas at one point married black women were having more kids than married white women, they are now having less," wrote Coates.

"People who are truly concerned about the percentage of out-of-wedlock births would do well to hector married black women for moral duty to churn out babies in the manner of their glorious foremothers," wrote Coats. "But no one would do that. Because it would be absurd."