genitourinary disorders
Male Hypogonadism
Etiology of Male Hypogonadism
 is insufficient to inhibit production of FSH and LH; hence, FSH and LH levels are elevated. The most common genetic cause of primary hypogonadism is Klinefelter Syndrome (47,XXY) . It involves seminiferous tubule dysgenesis, failure of spermatogenesis, Leydig cell hyperplasia, and a 47,XXY karyotype. Secondary hypogonadism is failure of the hypothalamus to produce gonadotropin-releasing hormone (GnRH), as in idiopathic hypogonadotropic hypogonadism, or of the pituitary gland to produce enough FSH and LH. In secondary hypogonadism,testosteronelevels are low and levels of FSH and LH are low or borderline normal. Any acute systemic illness can cause temporary secondary hypogonadism. Some syndromes of hypogonadism have both primary and secondary causes (mixed hypogonadism). The tablelists some common causes of hypogonadism by category. Some syndromes of hypogonadism (eg, cryptorchidism, some systemic disorders) affect spermatozoon production more thantestosteronelevels. 