Marginal rates of substitution in everything

Among married women aged 20‐45, we estimate the average marginal willingness to pay (WTP) for a spring birth to be 877 USD. This implies a willingness to trade‐off 560 grams of birth weight to achieve a spring birth. Finally, we estimate that an increase of 1,000 USD in the predicted marginal WTP for a spring birth is associated with a 15 pp increase in the probability of obtaining an actual spring birth.

Here is the full article, from the Journal of Applied Econometrics, by Damian Clarke, Sonia Oreffice, and Climent Quintana-Domeque, via the excellent Kevin Lewis.