Because it has been shown that genetic predisposition is of importance in determining which individuals develop ovarian cancer and that more than one gene may be involved, women with ovarian cancer and their relatives are studied to evaluate the influence of genetic and familial factors in the ovarian cancer phenotype. With the identification of the BRCA1 and BRCA2 genes, these families will be used to help determine which mutations are most frequent, along with the characteristics of ovarian cancer unlinked to these loci.