Health disparities in the United States have their origins as early as the prenatal period. Early life conditions including poverty and discrimination generate disparities in health over the life course that become further entrenched in the population through their transmission across generations. Parental mental health, which is strongly linked with social and economic disadvantage as well as child development, may play a key mediating role in the transmission of disparities across generation, but a persistent gap in the disparities literature is that both maternal and paternal psychopathology have not been fully considered as mechanisms nor measured using phenotypically validated approaches. As a result, though disparities in health are well documented, the developmental mechanisms that impact disparities at the very beginning of life are not, particularly those which lead to developmental deficits that emerge long before disease states. The National Institutes of Health (NIH) strategic plan (2016-2020) highlights the need for research to improve “understanding mechanisms that lead to disparities by race/ethnicity and socioeconomic status.” Such enhanced understanding is needed to clarify the etiology of disparities – particularly the specific exposures linked with social or economic disadvantage that impact early development. Advancing knowledge of the developmental mechanisms that generate disparities requires a more thorough understanding of how socioeconomic and race/ethnic status influence the determinants of development from gestation onward. To accomplish this, more in-depth measurement of potential causes of disparities is needed from more diverse samples starting earlier in the life course are needed than is currently available from existing studies.