NEWS YOU CAN USE: How When Harry Met Sally Explains Inequality: A new study says that educated people marrying each other has increased inequality by 25 percent.

Okay, it probably isn’t fair to blame Billy Crystal and Meg Ryan for our widening income gap. But it is fair to say that When Harry Met Sally tells us something about why the rich have been getting so much richer than everyone else. That’s high-earning college grads marrying each other—which a new paper estimates has increased inequality by 25 percent.

We used to live in a Mad Men world. Few men went to college, even fewer women did, and not many women, period, worked outside the home—not that they had many opportunities if they did. In 1960, 42.5 percent of married women hadn’t graduated from high school. 39.6 percent had only done that. And just 37.7 percent of all women had or were looking for a job. The stereotype is that men married their secretaries, if their wives did work, and there’s something to that—though highly-educated people did still pair up at high rates back then. . . .

That world is gone now. It’s gone, because more people, especially women, go to college. Because women have the chance to work—and earn—more. Because couples need two incomes to afford the same lifestyle that one used to buy. Because people who graduate from college cluster in neighborhoods away from those who don’t. And because people want more from marriage nowadays.

Among affluent marriages, it’s a When Harry Met Sally world, where working men and working women of similar education and income levels bond and marry over similarities—movies, art, paprikash—rather than the differences that defined traditional marriage (he works/she cleans). This new arrangement promises a better world, but it has increased inequality.

Read the whole thing.