This paper uses the 1918 influenza pandemic as a natural experiment for testing the fetal origins hypothesis. The pandemic arrived unexpectedly in the fall of 1918 and had largely subsided by January 1919, generating sharp predictions for long‐term effects. Data from the 1960–80 decennial U.S. Census indicate that cohorts in utero during the pandemic displayed reduced educational attainment, increased rates of physical disability, lower income, lower socioeconomic status, and higher transfer payments compared with other birth cohorts. These results indicate that investments in fetal health can increase human capital.