Most of the inherited epilepsies do not follow a Mendelian inheritance pattern but rather are complex disorders. This leads us to reconsider the traditional ethical framework applying to genetics, which is still based largely on the understanding of Mendelian inheritance, to ethically use the genetic tests likely to be forthcoming for the prevention and surveillance of epilepsies. This article is a review of the ethical issues raised by family studies of the epilepsies, in both a clinical and a research context. These issues include the use of genetic tests, the scope of genetic counseling, the upholding of the risk-benefit ratio in pharmacogenetics, as well as those related to the availability of treatments, health professionals' changing responsibilities, and the communication within families. A reasonable approach calls for a case-by-case determination of whether the benefit and harm of genetic testing outweigh benefit and harm of protecting autonomy and nonmaleficence.