Therefore, in face of the changes occurring in the physiology of the hypothalamic-pituitary gonadal axis from fetal life to puberty, the definition of hypogonadism should be extended to the impaired function of the ovaries or testes, as compared to what is expected for age, that involves a decreased function of the germ and/or somatic (Sertoli/granulosa, Leydig/theca) cell populations of the gonads, which can result in impaired hormone secretion (estrogens, progestins, androgens, inhibins, and/or AMH) and/or gamete production (4–6). This evidence concerns the gene AMH and hypogonadism.