FSHB and endometriosis: The FSH-lowering T allele of the FSHB promoter polymorphism (rs10835638; MAF 0.16) was associated with longer menstrual cycles [0.16 SD (c. 1 day) per minor allele; 95% confidence interval (CI) 0.12–0.20; P = 6 × 10−16], later age at menopause (0.13 years per minor allele; 95% CI 0.04–0.22; P = 5.7 × 10−3), greater female nulliparity [odds ratio (OR) = 1.06; 95% CI 1.02–1.11; P = 4.8 × 10−3] and lower risk of endometriosis (OR = 0.79; 95% CI 0.69–0.90; P = 4.1 × 10−4).