In BRCA1 P/LP variant carriers, the authors observed a reduction of 32% in breast cancer risk (OR 0.68; 95% CI 0.52–0.91; p = 0.008) for breastfeeding for at least one year and of 49% (OR 0.51; 95% CI 0.35–0.74) for over two years of breastfeeding [107]. This evidence concerns the gene BRCA1 and breast cancer.