What causes precocious puberty?

Peripheral Precocious Puberty
This form of early puberty is also called gonadotropin-independent precocious puberty. In peripheral precocious puberty, the abnormality is not in the brain but in the testicles, ovaries, or adrenal glands, causing overproduction of ....hormones, like testosterone and estrogens. Peripheral precocious puberty may be caused by:

• Tumors of the ovary, testis, or adrenal gland
• In boys, tumors that secrete a hormone called hCG, or human chorionic gonadotropin (pronounced kawr-ee-ON-ik goh-nad-uh-TROH-pin)
• Certain rare genetic syndromes, such as McCune-Albright syndrome or familial male precocious puberty
• Severe hypothyroidism, in which the thyroid gland secretes abnormally low levels of hormones
• Disorders of the adrenal gland, such as congenital adrenal hyperplasia
• Exposure of the child to medicines or creams that contain estrogens or androgens.