SHBG and hypogonadotropic hypogonadism: Although the decline in boys is partly from androgens [55], a comparable decline in boys with idiopathic hypopituitarism [56] or with isolated hypogonadotropic hypogonadism or complete androgen insensitivity [57] suggests that metabolic rather than neuroendocrine signals are the main driver of the late childhood decline in SHBG.