Hereditary ovarian carcinoma is heterogenous. There are at least three genetic variants, namely, hereditary site-specific ovarian carcinoma, hereditary breast/ovarian carcinoma syndrome, and Lynch syndrome II. Early age of onset characterizes these disorders. A crucial hallmark of these disorders is the integral association of extraovarian cancers, such as carcinoma of the endometrium and colon in Lynch syndrome II. We have described 24 pedigrees of ovarian cancer-prone families in order to depict the several differing heterogenous variants. Interest in hereditary ovarian cancer has increased remarkably, due in part to the fact that its surveillance has been wholly unsatisfactory, as have therapeutic measures. Prevention through prophylactic oophorectomy offers hope. However, there is a risk for extraovarian peritoneal serous papillary carcinoma, consonant with primary cancer of the ovary. This must be discussed with these at-risk patients. Until a biomarker of acceptable sensitivity and specificity is identified, the family history must remain the key to hereditary ovarian cancer diagnosis.