Introduction: This article discusses ethical, legal and social issues raised by the collection, storage and use of DNA in forensic databases. Review: The largest and most inclusive forensic database in the world, the UK National DNA database (NDNAD), leads the worldwide trend towards greater inclusivity. The performance of the NDNAD, criteria for inclusion, legislative framework and plans for integrating forensic databases across Europe are discussed. Comparisons are drawn with UK biobank that has started collecting DNA samples linked to medical records and, unlike the NDNAD, requires informed consent from volunteers, allows withdrawal of samples and only includes adults. The potential uses of research into genes associated with violent and ‘antisocial’ behaviour are discussed in the context of an increasing degree of surveillance in the UK. Conclusion: It should not be assumed that the benefits of forensic databases will necessarily override the social and ethical costs, regardless of changes to the criteria for inclusion or the permitted uses of samples and profiles. The expansion of forensic databases raises issues of relevance to the medical profession.