BRCA1 and breast cancer: In this study, we asked Ashkenazi Jewish women participating in a study of the breast cancer susceptibility genes BRCA1 and BRCA2 their perceptions of: (i) the population risk of breast cancer, (ii) their absolute risk of breast cancer and (iii) their comparative risk of breast cancer to determine predictors of breast cancer risk perception as a function of women's family histories and their actual absolute and comparative risks.