"A new study reveals that women's gains on the economic front may be contributing to a decline in the formation and stability of marriages," writes University of Chicago economist Richard Thaler in a New York Times column.

The study, by three of Thaler's Chicago colleagues, "found that traditional views of gender identity, particularly the view that the right and proper role of the husband is to make more money than the wife, are affecting choices of whom to marry, how much to work, and even whether to stay married."...