Maternity Leave - private loss and public loss?

This is a puzzling research finding. From The Long-Run Effects of America’s First Paid Maternity Leave Policy by Brenden Timpe. I am fully prepared to believe that a well-intended social policy ended up having negative outcomes because that is indeed the fate of most well-intended public policies.

However, I would have wagered that Maternity Leave entailed private gains at the expense of public losses (i.e. private participants gained but the magnitude of their benefit would have been less than the public cost expended to achieve that gain.) What Timpe is finding is that there is both private loss and public loss.

From the Conclusion section:

The robust body of literature on the effects of family leave policies has demonstrated clearly that parents, and especially mothers, greatly value the opportunity to take an extended absence after the birth of a child without surrendering a job match or the stream of income that comes with it. However, the recent nature of U.S. parental-leave policies has made it difficult to evaluate effects that may take years or even decades to materialize.

This paper provides the first estimates of these long-run effects from the United States by constructing a history of the country’s first expansion of paid maternity leave. While the policy greatly expanded the availability of maternity benefits and increased the amount of time new mothers spent on leave with a newborn child, it did not come without costs: I find evidence that women’s wages fell by about 5 percent, leading to a decrease in the incomes of middle-class families. Furthermore, these effects persisted into the next generation, reducing children’s educational attainment by 0.05 years and decreasing their probability of attending or graduating from college by 1.9 and 3.1 percent, respectively.

The finding of negative wage and family income effects, paired with a long-run decrease in children’s educational attainment, suggests maternity leave policies may not necessarily

I guess we wait for replication.