By using binary logistic regression analysis, we found that age at diagnosis of breast cancer, having any family history of breast or ovarian cancer, and having triple-negative breast cancer were associated with a 2.6-fold (confidence interval (CI), 1.4 to 4.8; P < 0.003), 3.5-fold (CI, 1.9 to 6.8; P < 0.0001), and 3.5-fold (CI, 1.91 to 6.3; P < 0.0001) increase in risk of being a BRCA1 or BRCA2 carrier, respectively. This evidence concerns the gene BRCA1 and breast cancer.