The size of a man’s penis is mainly determined by genetics, nutritional status, hormone levels, etc. Generally, if it does not affect the normal function, there is no need to worry. The penis is a male sex organ, mainly composed of two penile corpus cavernosum and one urethral corpus cavernosum. The size of the male penis is mainly affected by genetics, and when a direct relative has a larger penis size, his own penis size may be larger. Also, some men with adequate nutritional intake may have larger penises than malnourished men, but there are individual differences. In addition to these two factors, hormone levels can also affect the size of a man’s penis to some extent. Hypogonadotropic hypogonadism, caused by insufficient or excessive production of gonadotropins, affects the development of the penis. Usually, when men’s sexual function, urination and ejaculation are normal, there is no need to pay too much attention to the size of the penis. It is recommended that men learn about the penis and establish a correct physiological concept. When the penis area is accompanied by uncomfortable symptoms, they should consult a doctor in a timely manner.