Sunday birth rates in Ecuador have sharply declined, and the drop is larger among young cohorts in urban areas. These trends are attributed to an increase in cesarean births, which are generally scheduled during regular hospital hours. Multiple rounds of Health Surveys confirm that mothers with higher levels of education and socioeconomic status are more likely to give birth via cesarean and less likely to give birth on Sunday. Using administrative birth and earnings records we find that this selection process is strong enough to create an earnings differential between individuals born on Sunday and individuals born on other days. For instance, after controlling for age, education, gender and marital status, workers born on Sunday earn 2 percent less than comparable workers born on other days of the week. The Sunday-born earnings gap is larger for young cohorts in Quito and Guayaquil, precisely the same cohorts and urban locations where the decline in Sunday birth rates is largest.