A growing number of bioethicists, policy-makers, legal scholars, patient groups, and other critically involved parties in North America and Europe recently have started calling for a new ethical principle to gather participants into clinical and genetics research. While long-prevailing regimes of consent have held that people participate in the research process out of `altruism' (and hence do not merit more than nominal payment for their participation), the increasingly visible profits accruing to bioscience researchers, companies, and universities suggest that this research contract is producing a stark asymmetry. A move is afoot, therefore, to develop a principle of benefit-sharing through which to guarantee some form of returns to research subjects. This paper tracks some of the implications of the rise of this new ethic, tracing its travels from the world of bioprospecting to clinical and genetics research, and exploring how and why benefit-sharing matters to Latourian notions of science as politics. What might it mean, both for bioscience and for our ideas about politics and publics more generally, to think of research not just as a mode of `speaking for', in Latourian terms, but as a mode of giving back? I argue that in shifting the problem from one of dialogue to one of distribution, benefit-sharing proposals are also implicated in the constitution of the biosciences' publics in new ways.