Human capital is an important determinant of individual and aggregate economic outcomes, and a major input to scientific progress. It has been suggested that advances in genomics may open up new avenues to enhance human intellectual abilities genetically, complementing environmental interventions such as education and nutrition. One way to do this would be via embryo selection in the context of in vitro fertilization (IVF). In this article, we analyze the feasibility, timescale, and possible societal impacts of embryo selection for cognitive enhancement. We find that embryo selection, on its own, may have significant (but likely not drastic) impacts over the next 50 years, though large effects could accumulate over multiple generations. However, there is a complementary technology – stem cell-derived gametes – which has been making rapid progress and which could amplify the impact of embryo selection, enabling very large changes if successfully applied to humans.