Investing in the Womb: Identifying Gender Discrimination through the Lens of Prenatal Ultrasounds

In utero is a critical period of human development during which parents act on children’s behalf in health investments. These investments may have a profound impact on the life trajectory of a child. We investigate whether parents in Northern China who choose to carry the pregnancy to term allocate resources differently between their sons and daughters over the course of pregnancy after the sex of the child is disclosed to parents. Using unique and large-scale hospital electronic records of prenatal ultrasound scans and birth outcomes as well as a longitudinal survey of parents’ health behavior during pregnancy, we estimate how parental health behaviors and prenatal health investments change after parents gain access to gender information from post-20 gestational week ultrasound scans. In addition to the state-of-the-art difference-indifferences model, we employ a novel fetus fixed effect model to identify shifts in prenatal investments when information on child gender is disclosed. We document sex-selective prenatal investments as an early channel through which parents practice discriminatory behavior. We show that parents favorably shift certain parental health investments when pregnant with a boy. Specifically, the chance of exposure to passive smoking decreases while more mothers take nutrient supplements when parents expect boys compared to girls after receiving a post-20 gestational week ultrasound scan. Preferential prenatal treatment of males is greater for areas with stronger son preference. A set of key placebo tests using pre-pregnancy and early pregnancy behaviors reassure us that our identified effects are likely causal. Our findings have implications for eliminating gender discrimination and improving maternal and child health in the earliest stage of life. These findings also call for utilizing the window of opportunity during pregnancy to more effectively promote smoking cessation.