Individuals invest in their own health, but children rely on parents to act on their behalf, especially in the case of prenatal health. In this article, we ask, Do parents in the United States who choose to give birth allocate resources differently in the prenatal health of their sons and daughters when the sex of the child is known in advance? We pay special attention to prenatal health behaviors, which can be viewed as investment decisions, of first-generation immigrant parents from India and China, two countries with demonstrated son preference. Ultrasound receipt proxies for knowing fetal gender, enabling us to separate child sex-related biological differences from investment differences in sons’ and daughters’ health. There is evidence consistent with sex-selective abortions among Indian and Chinese populations, but among parents who choose to carry the pregnancy to term, our findings do not suggest that knowledge of child sex drives prenatal health investments in the United States, neither in the population as a whole nor among Indian and Chinese immigrants.