Bones stop growing at the age of 15 for boys and 13 for girls. Boys generally stop growing at the age of 9 and girls at the age of 8. As the hypothalamus acts on the pituitary gland, the pituitary gland secretes gonadotropin or luteinizing hormone and follicle stimulating hormone, promoting the testes of boys and the ovaries of girls to start secreting sex hormones. Tissues that are sensitive to sex hormones begin to grow faster, and bones will show significantly faster growth, scaling up in size. The epiphyses of boys and girls often close after four years of puberty, and the height growth of boys and girls during puberty is more than 8-10 cm, and they experience pubertal development, have mature secondary sexual characteristics and reproductive capacity, and their epiphyses close to reach adult lifelong height. In boys, the epiphysis closes completely at the age of 15, and in girls, the epiphysis closes at the age of 13, reaching adult lifetime height and stopping the growth of height.