Approximately 10% of the cases of breast cancer and invasive ovarian cancer are hereditary, occurring predominantly in women with germ-line mutations in the BRCA1 or BRCA2 gene. In deciding whether women with germ-line mutations in the BRCA1 gene should use oral contraceptives a possible increase in the risk of breast cancer needs to be weighed against the convenience of this means of birth control and its potential to reduce the risk of ovarian cancer. In women with BRCA2 mutations, oral contraceptive use has not been associated with an increased risk of breast cancer and does have the potential to reduce the risk of ovarian cancer. Prophylactic surgical options and intensified surveillance should, of course, be discussed with these patients.