What is a Micro Penis?

Micro penis is an unusually small penis, featuring a stretched flaccid length of less than 2 centimeters for a newborn male child and less than 4 centimeters for an adult. However, this definition is somewhat arbitrary and others have been proposed and used by different doctors.

The condition is diagnosed shortly after birth, just as the rest of the perineum, scrotum and penis are fully formed and there could be no doubt about size. The rate of occurrence is 0.6% of the male population.

The causes of this condition are commonly thought to be a low production of prenatal androgen. The male fetus does not receive the normal amount of androgen and so the penis does not reach the average size. Other potential causes are a deficiency in the fetus’ ability to synthesize the hormones testosterone and dihydrotestosterone or congenital growth hormone deficiency or inadequate stimulation of the pituitary gland.