Do I have a micropenis? Is the length of my penis normal? Is it too small compared to others, at rest or erect? These are questions that haunt many men often out of insecurities. But, what exactly is a micropenis? Should you even care?

So what is a micropenis?

In most cases, the micropenis is diagnosed at birth, and this problem originates during intrauterine life. The development of the boy’s genital system begins at the end of the first trimester of pregnancy. By the 8th week, the testes begin to produce testosterone and the penis is formed by the 12th week. Then, its growth continues over the following months.

The development of sexual characteristics continues after birth, under the influence of androgenic hormones.

The micropenis is usually the result of disturbances during one of these stages. When it is obvious that a child has a micropenis, in-depth examinations must complete the clinical observation: hormonal assays, pelvic ultrasound, cerebral MRI, etc…

These assessments make it possible to relate the micropenis to an underlying disorder (testicular insufficiency, pituitary insufficiency, etc…) which will then be treated.

At birth, we speak of micropenis if the penis of a little boy is less than 1.9 centimeters in length (after stretching and measured from the pubic bone to the end of the glans) and if this small size is not associated with any malformation of the penis.

At the onset of puberty, the limit to speak of micropenis is 4 centimeters, then less than 7 centimeters during or after puberty.

In adulthood, the “average” size of a penis is between 7.5 and 12 centimeters at rest and between 12 and 17 centimeters during an erection.

The main diagnostic step is to measure the length of the penis. It should be performed on the dorsal face (opposite the testicles) of the penis at rest, maintained in traction (but not excessively stretched, of course). It takes into account the distance between the base and the end of the exposed glans.

The following measurements define a micropenis:

  • Less than 1.9 cm (0.75 inches) at birth (child born at term)
  • Less than 2.6 cm (1.02 inches) at 1 year old
  • Less than 3.5 cm (1.25 inches) at 5 years old
  • Less than 3.8 cm (1.50 inches) at 10 years old
  • Less than 4 cm (1.57 inches) at rest in puberty and adulthood
  • Less than 8 cm (3.15 inches) erect in adulthood

Causes of a micropenis

The causes of micropenis vary. In a recently published study, of the 65 patients followed, 16 or almost a quarter, did not know the cause of their micropenis.

The causes of a micropenis can be hormonal (the most common case), linked to a chromosomal anomaly, a congenital malformation, or even idiopathic, that is to say without a known cause, knowing that environmental factors probably play a role. role.

Indeed, a study carried out in Brazil suggested an environmental cause for the appearance of a micropenis: exposure to insecticides during pregnancy could increase the risk of genital malformation.

However, most cases of micropenis are ultimately due to a hormonal deficit related to fetal testosterone during pregnancy. In other cases, testosterone is properly produced, but the tissues that make up the penis do not respond to the presence of this hormone. We then speak of tissue insensitivity to hormones.

How many men have a micropenis?

It is difficult to estimate the proportion of men who actually have a micropenis. The difficulty encountered by healthcare professionals in detecting a micropenis is that men often tend to find their penis too small. In a study, out of 90 men claiming to have a micropenis, 0% actually had a micropenis after examination and measurements by an expert.

In another recently published study, of 65 patients referred by their doctor to a specialist for micropenis, 20, or about a third, did not have a micropenis. These men thought they had too small a penis, but when a specialist took the measurement after stretching it, the size was normal.

Some obese men also complain about having a very short penis. In reality, it is often a “buried penis”, the part of which is attached to the pubis surrounded by pubic fat, making it appear shorter than it actually is.

Keep in mind that penis size does not affect fertility or male pleasure during sex. Even a small penis can lead to a normal sex life. However, a man who considers his penis too small can be self-conscious and have a sex life that is not satisfying to him.

People at risk

People who suffer from trisomy 21 or Klinefelter syndrome (this syndrome corresponds to a chromosomal abnormality, the boy having 47 chromosomes including one Y and two X while the normal karyotype is 46, XY for a man) have a higher risk to suffer from a micropenis.

The same is true for children whose mothers received anti-androgen therapy during their pregnancy. Androgen hormones, of which testosterone is a part, are responsible for male characteristics such as penis size, facial hair, hairiness, musculature, deep voice, etc.

Children who have cases of micropenis in their families are also at greater risk of developing micropenis in turn.

Prevention of micropenis

Since exposure to various chemicals is suspected to increase the risk of genital malformations in young boys, some doctors advise mothers to eat “organic” as soon as they want to have a child and during the pregnancy.

The main thing though to prevent a micropenis remains screening. A micropenis should be detected from birth in order to apply the appropriate treatment to the child.

In young children, in the event of a hormonal abnormality, treatment may consist of injections of testosterone, the dosage and regularity of which are set by the endocrinologist. This well-followed treatment increases the size of the penis. When the micropenis is caused by tissues of the penis that are insensitive to testosterone, this hormonal treatment has no effect.

The earlier the micropenis is detected, the faster the treatment is put in place, the more effective it will be. Treatment may also be necessary around puberty. After puberty, hormonal treatment is no longer effective because the tissues no longer react in the same way.

Surgical treatment of micropenis

In adulthood, when the micropenis has not been treated or when treatment has not been effective enough, surgery is another option. However, it does not always present convincing results.

Section of the suspensory ligament of the penis, which runs from the penis to the pubis, may be offered. It does not modify the penis in any way but partially detaches it from the pubis, making it appear longer. The observed gain is 1 to 2 cm in the flaccid state and 1.7 cm in erection. This lengthening comes at the cost of an unstable erect penis, since it is less attached to the pubis, which can make penetration more difficult.

Another solution is the injection of fat into the penis. Autologous fat injection involves injecting the subject’s fat under the skin of their penis. This in no way lengthens the penis, but makes it visually thicker. Only part of the fat put in place is not absorbed by the body over time (10 to 50% depending on the subject). The resorption may be uneven and lead to a “rosary” penis appearance.


A micropenis can have significant psychological repercussions, especially at the time of adolescence. It is, therefore, important that the person is helped and his doubts taken into account.

During examinations, doctors will look for abnormalities, particularly affecting the urinary meatus or the curvature of the penis. A micropenis doesn’t necessarily interfere with erectile and urinary function, but it does raise obvious relationship and psychological concerns.

Regarding the treatment, it is first medical, consisting of the injection of testosterone. Work is underway with promising results on the use of testosterone cream in children under 8 years old. At an older age, penile reconstruction (“penile lengthening”) may be offered.

However, we should emphasize, and several surveys have shown it, that many men who think they have too small a penis have a length perfectly in line with the average.

Elena Mars

Born in London, England and raised in Orlando, FL, Elena graduated from the University of Central Florida with a bachelors' degree in Health Sciences. She later received her masters' in Creative Writing  from Drexel University. She writes part-time for the Scientific Origin and focuses mostly on health related issues.