About a decade ago, a theory emerged: If men do more of the housework and child care, fertility rates will rise! Men have been doing increasingly large shares of the housework and child care. Fertility is lower than ever.

In fact, they're doing more in each generation, but fertility has continued to fall.

The original claim, that men's household work would buoy fertility, was based on cross-sectional data that was inappropriately given a causal interpretation. The updated cross-sectional data is as useful, and it affords no assurances about the original idea. We should move on.