Micropenis is a medical term that describes an unusually small penis. A common criterion is a dorsal (measured on top) erect penile length of at least 2.5 standard deviations smaller than the mean penis size.^[1] The condition is usually recognized shortly after birth. The term is most often used medically when the rest of the penis, scrotum, and perineum is without ambiguity such as hypospadias.

Causes

An erect penis with the micropenis condition.

After evaluation to detect any of the conditions described above, micropenis can often be treated in infancy with injections of various hormones, such as human chorionic gonadotropin or testosterone.

Most eight to fourteen year old boys referred for micropenis do not have the micropenis condition. Such concerns are usually explained by one of the following:

1. a penis concealed in 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.

Treatment

Hormone treatment

Man with micropenis, hypogonadism and gynecomastia

Regardless of the cause of micropenis, if it is recognized in infancy, a brief course of testosterone is often prescribed^[2] (usually no more than 3 months). This will usually induce a small amount of growth, confirming the likelihood of further growth at puberty, but rarely achieves normal size. No additional testosterone is given during childhood to avoid unwanted virilization and bone maturation. (There is also some evidence that premature administration of testosterone can lead to reduced penis size in the adult.)^[3]

Testosterone treatment is resumed in adolescence only for boys with hypogonadism. Penile growth is completed at the end of puberty, similarly to the completion of height growth, and provision of extra testosterone to post-pubertal adults will produce little or no further growth.

Surgery

Because hormone treatment rarely achieves average size, a number of surgical techniques like phalloplasty for penis enlargement have been devised and performed but are not generally considered successful enough to be widely adopted and are rarely performed in childhood.

In extreme cases of micropenis, there is barely any shaft, and the glans appears to sit almost on the pubic skin. From the 1960s until the late 1970s, it was not unusual for sex reassignment and surgery to be recommended. This was especially likely if evidence suggested that response to additional testosterone and pubertal testosterone would be poor. If parents accepted, the boy would be reassigned and renamed as a girl, and surgery performed to remove the testes and construct an artificial vagina. This was based on three now questioned assumptions:

1. gender identity and sex differences were solely a matter of social learning rather than biology.
2. a male with a penis too small to put into a vagina could not find a satisfactory social and sexual place in society.
3. a functionally acceptable vagina could be constructed surgically.

The center most known for this approach (Johns Hopkins Hospital) performed twelve such reassignments between 1960 and 1980, most notably, that of David Reimer, overseen by Dr. John Money. By the mid-1990s reassignment was less often offered, and all three premises had been challenged. Former subjects of such surgery, vocally dissatisfied with adult outcome, played a large part in discouraging this practice. As a result, sexual reassignment is rarely performed today for severe micropenis (although the issue of raising the child as a girl is sometimes still discussed.)^[4] Much inaccurate or exaggerated folklore on this topic is available on the internet. (See History of intersex surgery for a more complete discussion of this issue.)

See also

• Hypogonadism
• Intersex
• Penis size

References

1. ↑
2. ↑
3. ↑
4. ↑

External links

• Into the Hands of Babes, by Melissa Hendricks, Johns Hopkins Magazine
• Gender Self Reassignment in an XY Adolescent Female with Ambiguous Genitalia, from Pediatrics (PDF)
• Effect of penile size on nocturnal erections: evaluation with NPTR testing with men having micropenis from the International Journal of Impotence Research

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