Ovarian germ cell cancers are rare malignancies accounting for less than 5% of all ovarian cancers. We present a family in which three closely related women were diagnosed with ovarian germ cell malignancies. This family's cancer history prompted a family history investigation of women treated for ovarian germ cell malignancies in the Gynecologic-Oncology Clinic at the University of Wisconsin. One of the eight patients whose family histories were reviewed had an uncle who had been diagnosed with testicular germ cell cancer. A review found six other previously reported families in which more than one relative had been diagnosed with a malignant ovarian germ cell tumor. Additionally, several cases of families with both males and females diagnosed with germ cell cancers have been documented. The low incidence of ovarian germ cell cancers suggests that multiple occurrences in the same family may not be due to chance. Rather, it is possible that a gene conferring susceptibility to ovarian germ cell cancers, and possibly to germ cell tumors in males as well, is present in at least some of these families.