Micropenis (a very small penis): cause and treatment

A micropenis is a small penis that is smaller than 3.8 centimeters in an adult man and smaller than 1.9 centimeters in a baby. Although a clear cause cannot always be found, there is usually an abnormality, such as a testosterone deficiency or an abnormality in the chromosomes. This condition usually occurs together with another condition. What are the causes of a micropenis and what can you do about it?

What a micropenis entails

We speak of a micropenis (a very small penis) if it is smaller than 1.9 centimeters in a newborn boy and smaller than 3.8 centimeters in an adult man. This applies to a flaccid penis, measured from the pubic bone to the tip where the penis is extended to a maximum length. This is approximately equivalent to an erect penis. The normally shaped penis is smaller than the normal size reached for a child. This condition occurs in 0.6 percent of men.

Normal size penis

Research shows that the average height of an adult man is approximately 14.3 centimeters when erect. Yet there are major differences between them. An erect penis with a length of 11 to 21 centimeters is normal. Penis length will also vary in a resting state. For example, a man with a small penis at rest can achieve an above-average length when erect. The reverse can also occur. If a penis is less than 5 to 10 centimeters when erect, it is called a small penis. If the penis is even smaller, it is called a micropenis.


Although a clear cause is not always found, there are often certain conditions associated with a micropenis, such as an abnormality in the chromosomes, an insensitivity to the male hormone, a lack of the male hormone testosterone or an abnormality in the central nervous system . There may also be a developmental disorder in the second and third trimester of the growth of the embryo. If there is an abnormality in the level of hormones involved in the development of the sexual organs, it may be related to the pituitary gland or hypothalamus in your brain.


If parents discover this in their son at a young age, treatment can be devised. For example, testosterone can be administered to promote the growth of the sexual organs. This allows a normal penis size to develop in adulthood. If you suspect that you have a micropenis as an adult, go to the doctor. A specialist can determine what exactly is going on and possibly consider treatment.

Micropenis functioning

The penis usually functions normally, allowing the man to become aroused and get an erection. Furthermore, it can cause difficulties with sexual intercourse due to the small size of the penis. Yet a satisfying sexual relationship is possible. Many men have difficulty accepting themselves and are regularly bullied. Especially at a younger age, when showering together after exercise, attention is paid to the size of the penis. In some cases there is a low sperm count or even infertility.


Some men are candidates for surgical penis enlargement. Testosterone treatment is of no use for these men. During the procedure, skin can be removed from the forearm, which is used to lengthen the penis. The original penis is placed on the surface, keeping sensation intact as much as possible. A ureter and an inflatable erectile tissue are then placed in the artificial penis so that an erection becomes possible.

Gender change

In the past, it was often decided to operate on a boy with a micropenis as a baby, whereby the penis was completely removed. The external sexual characteristics became that of a girl and the child was raised as a girl. Later it turned out that most people were very unhappy with this choice in adulthood. It is better to raise a boy with a micropenis as a boy. Research shows that it is better not to opt for a gender change. Nowadays, penile reconstruction is increasingly becoming a real possibility.

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