Introduction

In many cases, genetic testing and screening can provide diagnostic information for improving health care. But the logic of the genes implies that diagnoses may be pre-emptive. Genetic information may be essentially prognostic information; its practical implications may be diverse and only partly predictable. The genome can rarely be ‘read’ (a difficult term in this context) in such a clear way that future events of health and disease can be forecast with security. Rather, in most cases the information takes the form of probabilities. This partial knowledge can clearly be useful; but because it is, at the same time, a new non-knowledge it can also be difficult to interpret and to handle. Furthermore, there may be stakeholders other than the patient themself involved: at-risk family members, carers, even institutions with interests. The construction, disclosure and exchange of personal genetic information that reveals things about one’s likely future in terms of potential disease is an emerging new space of ‘biosociality’ (Paul Rabinow’s term; cf. Rose 2007) in which ethical dilemmas arise.