DNMT1 and male infertility: When the DNMT1 CC genotype was used as the reference group, the CA genotype was significantly associated with increased risk for male infertility in Case Group I (adjusted OR, 1.50, 95% CI = 1.00–2.25, P = 0.048) and Case Group II (adjusted OR, 1.40, 95% CI = 1.05–1.86, P = 0.023).