The clomiphene stimulation test was validated for functional hypogonadotropic hypogonadism by Rabijewski, who showed that in men with functional hypogonadotropic hypogonadism, increases in testosterone levels in the clomiphene test >150%, LH >100%, and FSH >50% were associated with increased testosterone levels if treatment with clomiphene at a dose of 50 mg daily was continued for 3 months (8). Here, PLOD1 is linked to hypogonadotropic hypogonadism.