Many parents will have this question, my baby son development is normal? Is his penis too small? Why are his balls not big? The testicles and penis are the unique genitalia of men, and they are responsible for passing on the responsibility to the next generation, so it is necessary for parents to care about their children’s penis and balls. To solve the above questions, first we need to know what the size of the child’s balls and penis is during normal development. The volume of the testicles is in the process of change throughout life, the testicles of newborn children are relatively large, the development is delayed before puberty, rapid development near sexual maturity, and gradually become smaller after old age. The National Family Planning Commission Institute of Science and Technology survey data show that: the testicular volume of pre-pubertal boys is generally around 2ml, if the testicular volume > 4ml indicates that puberty has been initiated, the majority of boys testicular volume increases between the ages of 8-12, such as 10-12 years old still do not have any increase in the need for further examination. And the development of the penis is closely related to the changes in the endocrine of the body, data show that the length of the penis of newborn boys can reach 2.5-3.5 cm, the penis grows slowly after birth until puberty (around 12 years old), and will grow rapidly again after the beginning of puberty, only 5 years to reach the human level (4.5-10.1 cm when not erect). If your child does not reach these standards before and at puberty, you need to go to a regular hospital in time to find the cause. The general items that need to be checked are: ① Scrotal ultrasound: It can detect the size and location of the testicles, and understand the epididymis and spermatic veins. ② Sex hormones and growth hormones: such as blood FSH, LH, T, PRL, GnRH and other levels: can determine whether the boy has puberty initiation and understand whether there are abnormalities in hypothalamus and pituitary function. ③ Serum AMH (or MIS): is the best indicator to assess boys from birth to prepubertal development. Serum AMH is not only decisive in determining testicular function in young children, but also predicts their potential spermatogenic function. ④ Karyotype analysis: It is necessary to confirm the diagnosis of patients with chromosomal abnormalities (e.g., Creutzfeldt-Jakob sign). ⑤ AZF factor test: It can evaluate the genetic defects of male reproduction and thus better guide clinical treatment. ⑥ CT or MRI of the head: It can detect the presence of pituitary tumors or intracerebral occupying lesions, and thus assess pituitary function. The child is the treasure of the family, his growth is related to the happiness of the whole family, as parents should always pay attention to his growth and development, do not be careless, find abnormalities, please go to the regular hospital in a timely manner.