This dissertation analyzes sex-selective abortion in western India as a lived process with profound cultural, ethical, and demographic implications. Over the past three decades, selective elimination of female fetuses has emerged as a disturbing form of family planning across parts of Europe and Asia. In India, the practice remains widespread despite extensive efforts to combat it, with drastically skewed girl-to-boy ratios resulting in many locales. Drawing on eighteen months of ethnographic fieldwork with families and clinicians practicing sex selection, as well as with government officials and activists attempting to regulate it, this dissertation examines how prenatal sex determination marks fetuses with gender and incorporates them into local systems of kinship, biomedicine, and governance. Elucidating a kinship logic that renders daughters threatening and sons indispensable, I follow prospective parents and clinicians as they imagine divergent futures for children-to-be, navigate a clandestine black market, and employ specific biomedical techniques to produce and act on gendered fetuses. In the process of sex selection, fetuses become subject to complex ethical deliberations, familial struggles over reproductive decision-making, herbal and religious modalities of son production, and a host of public interventions aimed at saving daughters-to-be. I argue that the diverse actions around prenatal sex determination presuppose, shape, and intervene on a “gendered fetal subject”—an imagined or potential person whose liminal status (between human and non-human, between alive and un-alive) makes it a point of connection among households, clinics, and governance institutions. Tracing the production, transformation, and elimination of gendered fetal subjects reveals how kinship extends prenatally, as well as how fetuses become incorporated into social life. Furthermore, as suggested by prospective parents’ fraught reflections on the notion of a “necessary sin” (profoundly unethical but nonetheless unavoidable), understanding gendered fetal subjects provides an entry point for untangling the moral complexities of sex selection as a liminal form of violence—a gendered violation at the very threshold of human social existence.