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Micro Penis

Micro Penis Overview

Many men worry about the size of their penis; however, not many realise that there is an actual medical condition where the size of the penis is referred to as a "Micropenis".

The condition is usually recognized shortly after birth. The term is most often used medically when the rest of the penis, scrotum, and perineum are normally developed and only penis is small.

How small is a Micropenis?

The condition refers to any penis which, when stretched, is 2.5 standard deviations below the mean size for the age of the patient.

What does 2.5 standard deviations below the mean work out as?

In adults, the condition refers to any penis smaller than 2.8 inches in length.
In infants, a Micropenis is classed as any penis that is less than 0.75 inches in length. This is considered significantly smaller than a "normal" male newborn's penis, which is between 1.1 and 1.6 inches in length when stretched gently.

What problem does having a Micropenis cause?

Having a micro-penis can cause several problems, including difficulty urinating and having sexual intercourse.
Fertility can also be affected. Some people with Micropenis have a low sperm count which results in infertility or decreased fertility.
The condition can also have a major impact psychologically. Many men with the condition have very low self-esteem and some even suffer from depression.

Micro Penis

  • Causes
  • Treatment

    What causes Micropenis?

    Micropenis is caused by the male baby’s penis failing to elongate after the first trimester of pregnancy.

    The cause of this is thought to be a hormonal problem. Specifically, it is thought to be due to insufficient levels of testosterone, a male sex hormone.

    The inadequate levels of testosterone may come as a result of inadequate production of testosterone during the second and third trimesters of pregnancy or as a result of the unborn child not responding to the produced testosterone.

    Research carried out has shown that genetic mutations of the SRD5A2 gene that is the gene, which codes for enzyme 5-alpha reductase, which is turn processes testosterone.

    Researchers have also found that there may be a genetic condition, which makes boys more susceptible to the development of Micropenis, triggered by factors in the environment namely dioxins and pesticides.

    Incidence of Micropenis

    Despite not being commonly discussed, the condition is thought to affect 1 in 200 males that are born.

    Not all small penis is micro penis. Some may be

    1. Concealment of the penis in the suprapubic fat (extra fat around the mons pubis).
    2. A large body and frame for which a prepubertal penis simply appears too small.
    3. Delayed puberty with every reason to expect good future growth.


      Early diagnosis of "true Micropenis" is important, because it allows for various treatment options to be utilized early. The first step in the diagnosis of Micropenis is the physical examination of the patient's external genitalia.

      Historically people considered changing sex of the child from male to female if there was a micro penis.

      Nowadays, according to the UK Intersex Association (UKIA) views cosmetic surgery of the genitals to reassign an infant's gender from male to female, solely due to the child having a small penis, is same as "child abuse".

      Instead, they advocate hormone therapy called testosterone replacement. This can produce a penile length within the "normal range".

      Micropenis can also be treated with surgery called phalloplasty.

      Phalloplasty often involves using skin from the patient's forearm. This skin is wrapped around the native penis and some times an inflatable penile prosthesis is inserted to provide an erection.

      Researchers have found that this procedure produced a penis which could be used for sexual intercourse on a regular basis and that remained stable for the long-term.


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