In 2015, the UK became the first country in the world to make legal a set of 'mitochondrial donation' techniques. These new reproductive technologies have the potential to enable women with diseases that are normally inherited via the mitochondrial genome to have children with healthy mitochondria. The extensive deliberations that preceded the legalization of these techniques involved a form of division of advisory labour that is common when new technologies are introduced. Groups like the Nuffield Council on Bioethics focused on the ethics of mitochondrial donation, while scientific issues were instead given over to more specialised groups of technical advisors. I use the case of mitochondrial donation to argue against the possibility of any strict separation of scientific and ethical evaluation, and also to argue that efforts to divide labour in these ways threaten to obscure important controversies around new technologies. I close by showing how these worries relate to more general philosophical issues around the 'value-ladenness' of science.