Under normal physiological conditions, the growth and development of the human body is regulated by the brain in a strict chronological manner. In the human brain, near the hypothalamus, there is a special functional structure that acts as an electrical switch that controls the onset of puberty in children. As we grow older, the central nervous system gradually develops and matures, that is, when girls are about 11-13 years old and boys are about 12-14 years old, the “switch” of puberty development is turned on by the command of the central nervous system, and the hypothalamus starts to secrete gonadotropin-releasing hormone in a pulsatile manner. The gonadotropin-releasing hormone then acts on the pituitary gland to synthesize and release gonadotropin, which in turn acts on the gonads (testes or ovaries), urging them to produce and secrete large amounts of sex hormones (mainly testosterone and estradiol), which have a very wide range of physiological effects. -puberty. It is well known that during puberty, both boys and girls rapidly grow taller and eventually stop growing to reach their normal adult lifetime height. However, the body structure of the two sexes will undergo very different changes. Boys will have a laryngeal node, voice becomes low, muscles become developed, body becomes strong and powerful, penis grows significantly, and seminal emission; girls will have bilateral breast development, fat deposits in the buttocks, body becomes full and round, uterus enlarges, and periodic menstruation occurs. This is the course of normal adolescent development. The cause of these changes is the mysterious sex hormones – androgens produced by the testes in boys or estrogen produced by the ovaries in girls. Today, worldwide, along with social progress, economic development, and increasing environmental pollution, there is a tendency for children to start puberty at an earlier age. However, if girls have obvious or progressive breast development before the age of 8, and boys have secondary sexual characteristics such as laryngeal nodes and lowered voice before the age of 9, it should be regarded as precocious puberty; on the contrary, when girls or boys reach the age of 15-16, but still delayed to see any trace of puberty development, it is called delayed puberty development.