Understanding the links between climate and fertility and reproductive health outcomes in poor countries is a major ethical and policy imperative. However, doing so will require researchers in population sciences and in earth and climate sciences to merge their expertise. To this end, the dominant theoretical frameworks and readily available geospatial population data used by social scientists provide a starting point for climate and physical scientists to think about the mechanisms that link climate and weather to fertility and reproductive health, and available climate data and analytic strategies can be used to develop research that considers different scales of influence.