Generally speaking, the early development of secondary sexual characteristics such as breast enlargement or menstruation within ten years old in girls within eight years old, and the early development of secondary sexual characteristics such as testicular enlargement and pubic hair in boys within nine years old can be diagnosed as precocious puberty. True precocious puberty: Most of the causes are unknown, in addition to the early development of secondary sexual characteristics, also has the ability to reproduce, generally short stature. Pseudosexual precocious puberty: Most of them are caused by tumor, cortical hyperplasia, health care products and environmental factors, which do not have reproductive ability and do not affect height.