Jon Birger writes,

Multiple studies show that college-educated Americans are increasingly reluctant to marry those lacking a college degree. This bias is having a devastating impact on the dating market for college-educated women. Why? According to 2012 population estimates from the U.S. Census Bureau’s American Community Survey, there are 5.5 million college-educated women in the U.S. between the ages of 22 and 29 versus 4.1 million such men. That’s four women for every three men. Among college grads age 30 to 39, there are 7.4 million women versus 6.0 million men—five women for every four men.

In the Mad Men era, when there were men than women who had graduated college, some men married “down.” Now, when there are more women than men graduating college, we have assortative mating. The result is that women have a harder time finding a “suitable” husband.

And there is this: