Patients with testicular dysgenesis syndrome in general exhibit an elevation of Follicle-Stimulating Hormone (FSH), but in these patients, very frequently, even Luteinizing Hormone (LH) is above the reference range. The latter can work as a growth factor for Leydig cells. Since exogenous testosterone can suppress LH levels, it could be that androgen therapy could revert the LH-induced growth stimulation of Leydig cell compartment.