Earlier menarche (≤14 years old) increased the BC risk by 3.49-fold in BRCA2 mutation carriers (95% CI=2.03–6.00) and 3.30-fold in non-carriers with FH of BC (95% CI=1.73–6.34), but was insignificantly associated with BC in BRCA1 carriers and early-onset BC non-carriers (P-heterogeneity=0.047). Here, BRCA1 is linked to breast cancer.