Many unmarried men or post-marital sexual relationship disharmony, the size of the penis is very sensitive, always feel that their penis is smaller than others, the visual appearance of the penis is not beautiful, patients are often reluctant to public toilets or public baths, such as around the size of the penis doubts unfortunately often transformed into low self-esteem and anxiety, so that they suffer for no reason. Even because of the greater psychological burden, sexual dysfunction after marriage, can not meet the wife’s sexual requirements, resulting in tension between the couple and even divorce. So what is the size of the normal penis? In the weak state shorter than 4 cm, erection after not more than 8 cm, can be regarded as penis short. However, this is not to be confused with micropenis caused by developmental abnormalities. The former belongs to the normal range of individual differences, as long as the erection is normal, and supplemented by appropriate sex knowledge education, can fully achieve the requirements of normal sex life. True micropenis is the result of congenital developmental abnormalities, usually referring to penile draw lengths shorter than 2.5 cm before puberty and less than 5 cm after puberty, and accompanied by abnormal development, no erectile function, poorly developed secondary sexual characteristics, sexual dysfunction, no fertility, no sperm production, etc. There are also men who mistakenly believe that the stronger and taller the physique, the bigger the penis will be. In fact, of all the organs in the human body, the penis has the least constant relationship with overall development. The reality is that the size of the penis is not directly related to the body away from the weight and physical strength. Therefore, a thick skeleton and strong muscles do not equal a large penis, on the contrary, a person with a small skeleton or on the thin side does not necessarily have a small penis in a weak state. Of course, the human penis is also as tall, short, fat and thin as there is a big difference, but also the length of the thickness of different. In addition, when measuring the length of the penis, if you measure it yourself instead of going to the hospital, you should pay attention to a few points: the size of the penis varies in a weak state, such as in tension, fatigue, cold, the penis will be relatively shortened. In the case of the same person, the size of a well-developed penis is constant after full erection. Therefore, the size of the penis is usually measured by the length after erection. However, because the person being examined is nervous or uncomfortable with the examination environment, he or she is often unable to have a full erection during the examination and therefore the length of the erection is often represented by the length of the penile traction. The so-called penile pull length refers to the length of the penis to the urethral opening of the head of the penis by using the thumb and index finger to hold the penis at the coronal groove to lift the penis flat, pull the penis to make it fully extended and then use a hard ruler to hold the penis at the root of the pubic symphysis with slight force. The reasons for the formation of penis short are various, there are congenital factors, there are also acquired factors, the influence of genetic genes is the most fundamental, common causes are as follows: (1) during maternal pregnancy due to improper administration of drugs, affecting the secretion of androgens, Mr. insufficient; (2) lack of nutrition and prime elements of robust sexual function, the formation of congenital dysplasia; (3) during the development of adolescents, nutrition is insufficient to play a growing (4) excessive sexual life, weakness or masturbation too often during the development of adolescents, so that the kidneys do not have the energy to grow and develop the sexual organs during development, forming a short penis; (5) suffering from orchitis, cryptorchidism, testicular insufficiency and endocrine imbalance, androgen deficiency; (6) prepuce is too long, lacking the necessary space for growth, hindering the development and growth of the penis. For men with a small penis, in addition to unsightly, more worried about its impact on sexual function, in fact, it is not necessary. In the process of sexual life, in fact, the penis erection is the most important, the size of the penis is not very important, that is, the completion of sexual action is mainly dependent on the hardness and strength of the penis, rather than the length of the penis, on the contrary, many penis is large but has low sexual function. Indeed, men with a small penis, in changing the position of sexual intercourse or take measures to stimulate each other’s emotions, in order to improve the interest of sexual intercourse, the same may obtain a satisfactory sex life. Some scholars have investigated more than 800 cases of normal male penis in China, the length of the weak state is 4 to 12 cm, the difference can not be said to be large, but they all have a normal sex life and fertility. Whether it is true that the penis is short or acquired by men with higher requirements, penis enlargement and lengthening is a common means. Traditional penile enlargement surgery involves transplanting or injecting fillers into the corpus cavernosum, because the fillers are placed outside the white membrane, and “how much is put in is how much”, and cannot be actively expanded; moreover, some fillers are absorbed or fibrotic, resulting in retraction or deformation in appearance. At present, the “white membrane augmentation phalloplasty” is performed by first lengthening the penis by loosening the ligaments, then symmetrically cutting the white membrane of the penis, and then taking two venous flaps from the patient’s thigh and connecting them to the cut area as a patch. In this way, the surgery had the effect of a sewer making small pants bigger and thickening the patient’s penis. After the surgery, the surgeon measured the patient’s penis and it nearly doubled in size when it was weak compared to the pre-operative size.