Emerging technologies make genomic analyses more efficient and less expensive, enabling genome-wide association and gene-environment interaction studies. In anticipation of their results, funding agencies such as the US National Institutes of Health and the Wellcome Trust are formulating guidelines for sharing the large amounts of genomic data that are generated by the projects that they sponsor. Data-sharing policies can have varying implications for how disease susceptibility and drug-response research will be pursued by the scientific community, and for who will benefit from the resulting medical discoveries. We suggest that the complex interplay of stakeholders and their interests, rather than single-issue and single-stakeholder perspectives, should be considered when deciding genomic data-sharing policies.