Conditions & Treatments

Micropenis

Micropenis is defined as a normally structured penis that is below the normal size range for an infant.

Micropenis

What is micropenis?

Micropenis is defined as a normally structured penis that is below the normal size range for an infant. Normally, the length of a newborn boy's penis is between 2.8 to 4.2 centimeters (1.1 to 1.6 inches) with a circumference of 0.9 to 1.3 centimeters (0.35 to 0.5 inches). This measurement is taken by carefully stretching the penis and measuring from the tip of the penis to the base of the penis. A penis length of less than 1.9 centimeters (0.75 inches) is usually considered micropenis.

What causes micropenis?

Micropenis can occur alone, but usually occurs in combination with other disorders. Hormone disorders that cause an abnormal level of the hormones involved in the development of the sexual organs may be seen in combination with micropenis. This can involve the pituitary gland or the hypothalamus.

What are the symptoms of micropenis?

While each child may experience symptoms differently, the most common finding with micropenis is an infant penis size that is less than 1.9 centimeters when stretched gently. In some cases, low sperm count, resulting in infertility or decreased fertility, is found in adulthood. Micropenis may or may not be seen in conjunction with other disorders. Always consult your child's doctor for a diagnosis.

How is micropenis diagnosed?

Diagnosis is usually made by physical examination. Your child may then be referred to several specialists including a pediatric urologist (a doctor who specializes in disorders and care of the urinary tract and the male genital tract) and a pediatric endocrinologist (a doctor who specializes in hormones).

What is the treatment for micropenis?

Specific treatment for micropenis will be determined by your child's doctor based on:

  • Your child's age, overall health, and medical history

  • The extent of the condition

  • Your child's tolerance for specific medications, procedures, or therapies

  • Expectations for the course of the condition

  • Your opinion or preference

There is no cure for micropenis. Hormone therapy may be indicated for some children to stimulate penile growth. Other treatment options will be discussed with you.

Treatment Programs


Massachusetts General Hospital understands that a variety of factors influence patients' health care decisions. That's just one reason why we're dedicated to ensuring patients understand their diagnosis and treatment options. Because a single option might not serve all patients, we offer a wide range of coordinated treatments and related services across the hospital. Patients should consult with their primary care doctor or other qualified health care provider for medical advice and diagnosis information.

Select a treatment program for more information:



MassGeneral Hospital for Children

  • Pediatric Urology
    The Pediatric Urology Service at MassGeneral Hospital for Children provides care ranging from simple circumcisions to the most complex of urinary and genital anomalies in children from birth to young adulthood.

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Departments and Centers at Mass General have a reputation for excellence in patient care. View a list of all departments.