Another fact is the influence of hypergamy, which means that women typically choose a mate (husband or boyfriend) who earns more than she does. Men don't have the same preference for a higher-earning mate.

While women prefer to HAVE a higher-earning partner, men generally prefer to BE the higher-earning partner in a relationship. This simple but profound difference between the sexes has powerful consequences for the so-called pay gap.

Suppose the pay gap between men and women were magically eliminated. If that happened, simple arithmetic suggests that half of women would be unable to find what they regard as a suitable mate.