Until the recent discoveries of RAD51C and RAD51D [6,7], the most notable genes contributing to the 4.6-fold relative risk conferred by hereditary ovarian cancer susceptibility had been BRCA1 and BRCA2. Deleterious mutations in BRCA1 lead to a lifetime ovarian cancer risk of approximately 20%–50% and in BRCA2 of approximately 10%–20% (see Table 1). Here, BRCA1 is linked to familial ovarian cancer.