Married and unmarried.

The real class distinction in America.

Estimates vary widely, but scholars have said that changes in marriage patterns — as opposed to changes in individual earnings — may account for as much as 40 percent of the growth in certain measures of inequality. Long a nation of economic extremes, the United States is also becoming a society of family haves and family have-nots, with marriage and its rewards evermore confined to the fortunate classes.

“It is the privileged Americans who are marrying, and marrying helps them stay privileged,” said Andrew Cherlin, a sociologist at Johns Hopkins University....

Married couples are having children later than they used to, divorcing less and investing heavily in parenting time. By contrast, a growing share of single mothers have never married, and many have children with more than one man.

“The people with more education tend to have stable family structures with committed, involved fathers,” Ms. McLanahan said. “The people with less education are more likely to have complex, unstable situations involving men who come and go.”

She said, “I think this process is creating greater gaps in these children’s life chances.”

It's hard to see how this is going to get any better over time.

IN THE COMMENTS: Paco Wové said:

The Gods of the Copybook Headings have come calling for the lower middle class.