There were no relevant group differences in age, BMI, or the serum FSH, LH or estradiol concentrations at baseline; however, the serum testosterone concentrations were significantly lower in the endometriosis group (0.19±0.14 ng/ml) than in the control group (0.43±0.22 ng/ml, p = 0.0012) at baseline. The gene discussed is PLOD1; the disease is endometriosis.