Most breast cancer is multifactorial in origin, but dominantly inherited genes are implicated in the development of approximately 5-10% of breast cancer as a whole. The identification of the BRCA1 gene, thought to account for 2% of all breast cancer and be present in almost all families affected by breast and ovarian cancer, makes testing for susceptibility to breast and ovarian cancer possible for the few families in which researchers have identified a gene mutation. Genetic counselling, by medically qualified geneticists, is available for people with rare genetic conditions caused by gene mutations. In this article, the authors describe their first experience of BRCA1 gene testing in 23 family members. They identify a unique role within a new specialty, cancer genetics, for specialist nurse practitioners in genetic testing and counselling.