Modern mating rituals have increased income inequality:
In the past, women tended to “marry up”: nurses married doctors and secretaries their bosses. But as women increased their presence on campuses and then began to bring home more money, college-educated men decided that they were better off marrying one of their own. Think of the implications for household earnings. A lawyer was always likely to earn more than a plumber—but today, plenty of upper-income households are headed by two lawyers. That considerably widens the gap between a power couple and a lower-middle-class duo. Sociologist Christine Schwartz has estimated that assortative mating brought about a 25 percent to 30 percent increase in inequality among married-couple families between 1967 and 2005.