Some children may start the development from girl to woman or boy to man earlier than normal. Starting puberty early is referred to as precocious puberty. Only one in ten girls passes through puberty before eleven, and boys before twelve years of age. Over the last two centuries, the average age of puberty has dropped by more than 18 months due to better nutrition and health.
If both parents started puberty early, then there is an inherited tendency for their children to do the same.
Most causes of precocious puberty are common to both sexes.
If sex hormones are given to children deliberately or accidentally by tablet or injection, adult sexual characteristics will develop, although true puberty may not occur, and the child will remain infertile. Tumours of the ovary, testes, brain or pituitary gland under the brain may also stimulate production of sex hormones at an early age.
Other causes include:
- hydrocephalus (too much fluid around and in the brain),
- Cushing syndrome (an over production of steroids, or taking large doses of cortisone),
- encephalitis (infection of the brain),
- congenital adrenal hyperplasia (adrenogenital syndrome – overactivity of the adrenal glands),
- Albright syndrome (abnormal bone formation),
- tuberous sclerosis (convulsions and an intellectual disability).