Partial precocious puberty is a self-limiting disorder in which only the breasts or pubic hair develop early without other symptoms of sexual development. For example, premature breast development refers to isolated breast development without other sexual characteristics in girls before the age of 8. The onset of the disease is usually from birth to about 2 years old, and is characterized by breast enlargement, but no nipple or areola enlargement or pigmentation, and no other sexual characteristics development or growth acceleration. The disease is a variant of precocious puberty and is mostly benign and self-limiting, but only rarely does it develop into true precocious puberty. In one study, breast tissue was found to be palpable in 5% of Italian children aged 1 year. The reasons for this are unclear, as some now suggest that the gonadal axis is active in childhood, that the breasts can increase in size up to early puberty after repeated and repeated administration of estrogen, and that when estrogen disappears, the breast shape does not deteriorate rapidly with it. It is also possible that exogenous estrogen, through ingestion, skin absorption, or other exposure, can also cause premature breast development. In the literature, there has been an epidemic of breast development in Italy that may have been caused by high levels of estrogen in meat. The liver of animals can concentrate estrogen, which can also cause early breast development when consumed in large quantities over a long period of time. It has also been reported that breast milk contains gonadotropin-releasing hormone, which can occasionally cause early breast development. In most girls, breast tissue degenerates within 6 months to 6 years after the diagnosis of prematurity, and about 10% of children with prematurity develop breasts until puberty. No special treatment is usually needed. Other conditions such as simple pubic hair appearances are more common in girls. It often occurs in prepubertal children. Clinically, there is a small amount of pubic and axillary hair with accelerated growth, but no development of external genitalia or other sexual characteristics. It is thought to be related to premature secretion of dehydroisosterone by the adrenal cortex or premature sensitivity of the pubic (axillary) hair follicle receptors to the hormone, and does not require special treatment. Isolated early menarche can also occur in girls before the age of 4 years, resulting in vaginal bleeding without other features. No special treatment is required.