In February 2015, British Members of Parliament approved a proposed change in law that would enable the conception of three-person babies. This legislative amendment would allow UK fertility clinics to carry out mitochondrial donation, an IVF technique that involves biological material from three people. Rather than providing us with a set of problems to be resolved or challenged in a one-sided fashion, the dualisms that intimately underpin work across the sciences (social and natural) provide instead a fertile ground for examination and exploration, indeed a productive ground, one in which conceptual developments thrive. Thus, if biomedicine continues to be caught in the clutches of the Cartesian dichotomy, these dichotomies have also been good to think with. Indeed, it is by attending to developments in science, medicine and technology that we continue to refine the conceptual ground that has become a hallmark of anthropology and sociology.