This article considers how we should frame the ethical issues raised by current proposals for large-scale genebanks with on-going links to medical and lifestyle data, such as the Wellcome Trust and Medical Research Council's 'UK Biobank'. As recent scandals such as Alder Hey have emphasised, there are complex issues concerning the informed consent of donors that need to be carefully considered. However, we believe that a preoccupation with informed consent obscures important questions about the purposes to which such collections are put, not least that they may be only haphazardly used for research (especially that of commercial interest)—an end that would not fairly reflect the original altruistic motivation of donors, and the trust they must invest. We therefore argue that custodians of such databases take on a weighty pro-active duty, to encourage public debate about the ends of such collections and to sponsor research that reflects publicly agreed priorities and provides public benefits.