The male reproductive system usually stops developing around the age of 18 to 20, but this time is influenced by many factors such as the environment. Normally, male reproductive organs can stop growing after the end of puberty, mostly around 18 to 20 years old. It may also be related to factors such as genetics, environment and nutrition. The male reproductive organs develop slowly before puberty. After puberty, the gonadotropins secreted by the hypothalamus and pituitary gland can induce the rapid development of the testes, epididymis and other organs. As the testes develop and mature, their secretion of androgens can also gradually increase. Under the action of androgens secreted by the sex organs, the reproductive organs will develop gradually, and the reproductive organs may not develop again after the end of puberty, and are relatively stable in adulthood. If endocrine dysfunction occurs in the hypothalamus and other organs, it may lead to abnormal sexual development during puberty, with precocious puberty and delayed pubertal development.