High parity has been associated with a lower risk of breast cancer (in range of 0.7) among BRCA1/2 PV carriers, and breastfeeding with a lower risk (in range of 0.6) among BRCA1 PVs carriers (32, 33), similar to the lower risks associated with high parity (in range of 0.7) and breastfeeding (in range of 0.8) in the general population (30, 31). This evidence concerns the gene BRCA1 and breast cancer.