There has been a rapid expansion of genetics research in the field of cancer since cancer predisposing genes are now known to cause a proportion of common cancers as well as rarer cancer syndromes. As a result, the psychosocial impact of being at high risk of cancer has become a focus of evaluation, and studies are being reported which set out to evaluate both the uptake and psychological outcome of genetic counselling, testing and surveillance. Available data concerning psychological aspects are reviewed, including for example, possible implications of genetic testing, attitudes and uptake of breast screening and accuracy of women's risk estimates. Work is in progress to assess the more controversial areas of prophylactic mastectomy, and chemoprevention. Other research examines the longer term impact of belonging to a Cancer Family, and of interventions offered to high risk families. This is crucial since the uptake of counselling and testing is likely to be much greater in cancer prone families than those with other genetic disorders, yet detection and prevention strategies are still unevaluated for important genetically determined cancers such as breast cancer.