Mendelian randomization (MR) analyses indicated a genetically causal protective effect of FSH on risk of F-ALL (OR (95% CI) 0.776 (0.678–0.888), P = 2.15 × 10−4) and F-EXCL (0.716 (0.604–0.850), P = 1.26 × 10−4) (Supplementary Table 11). This evidence concerns the gene BRD2 and acute lymphoblastic leukemia.