Many women with breast cancer have first-degree (mother, sister, or daughter) or second-degree (aunt) relatives with breast cancer. Mutations in 2 genes increase risk for breast and ovarian cancer: breast cancer susceptibility genes 1 and 2 (BRCA1 and BRCA2). These mutations are more common in certain ethnic groups, such as Ashkenazi Jewish people. However, not all women with a family history of breast or ovarian cancer have one of these mutations, and not all women with one of these mutations will develop cancer. Genetic testing could identify women who should consider procedures to reduce cancer risk (intensive screening; medication; or surgical removal of breasts, ovaries, or both). However, because not all women who have a BRCA mutation develop cancer, identification of mutations may also needlessly expose women to anxiety or unnecessary procedures.