One area of the brain, the hypothalmus, secretes hormones (GnRH) to stimulate the pituitary gland. In response, the pituitary gland (located near the brain) secretes other hormones (FSH and LH).

These, in turn, stimulate the ovaries (female) and testes (male) to secrete hormones that are responsible for normal sexual development in puberty. Any disruption in this cascade causes a deficiency of the sex hormones and halts normal pubertal sexual maturation.

Failure of the hypothalamus is most commonly a result of Kallmann syndrome. Kallmann syndrome is an inherited disorder that usually includes a disorder of the sense of smell. Failure of the pituitary may result from empty sella syndrome, pituitary tumors (craniopharyngioma), head injuries, or other causes.