Micropenis is a medical term for a penis, usually diagnosed at birth, that is well under the normal size range for an infant. In every other way, including structure, appearance, and function, a micropenis is like any other healthy penis.

Before birth, a male infant’s genitalia develop in response to certain hormones, mainly androgens.

If his body doesn’t produce enough androgens or if the body doesn’t respond normally to androgen production, one result can be a micropenis, also called a microphallus.

Medical disorders that affect the pituitary gland or the hypothalamus, both of which play key roles in hormone production, are associated with micropenis.

While a micropenis can develop on its own, with no other hormone-related conditions, it can occur along with other disorders.

It’s not always clear why some boys are born with a hormone disorder that causes micropenis. Family history of micropenis may raise the risk. A 2011 French study, suggests that fetal exposure to pesticides and other chemicals may increase the chances of micropenis development.

What it is and what it isn’t

Assuming there are no other health concerns, a micropenis functions the same as a normal, healthy penis. The ability to urinate and become erect shouldn’t be affected.

A micropenis is sometimes associated with a lower sperm count, however, so fertility may be reduced.

In addition to getting a personal and family medical history, the doctor will do a physical examination. That should include a proper measurement of the penis.

To make a thorough diagnosis, the doctor may order a blood test to check for hormone disorders.

If you suspect your baby has a micropenis, consult a pediatric urologist or a pediatric endocrinologist.

A urologist is a doctor who specializes in the health of the urinary tract and male reproductive system. An endocrinologist specializes in hormone disorders.

If you have any concerns about your own genitalia, see a urologist who treats adult patients.

What defines a micropenis is its stretched penile length (SPL).

Stretched penile length (SPL) for babies

The average male infant’s SPL is 2.8 to 4.2 centimeters (1.1 to 1.6 inches), while the length of a micropenis is defined as less than 1.9 cm (0.75 in.).

An SPL that is somewhere in between 1.9 and 2.8 cm in length may be considered shorter than average, but not a micropenis.

SPL for boys

For prepubescent boys who are 9 to 10 years old, for example, the average SPL is 6.3 cm (2.48 in.), meaning an SPL of 3.8 cm (1.5 in.) or shorter would be considered a micropenis.

An SPL between 3.8 cm and 6.3 cm would just be considered shorter than average.

SPL for adults

In an adult, the average stretched penile length is about 13.24 cm (5.21 in.). An adult micropenis is a stretched penile length of 9.32 cm (3.67 in.) or less.

GroupMicropenis SPL measurement
Newborn babies<1.9 cm (0.75 in.)
Older, prepubescent boys<3.8 cm (1.5 in.)
Adult men<9.32 cm (3.67 in.)

The proper way to measure for a micropenis is to gently stretch it and measure the length from the tip to the base, closest to the body.

Micropenis is actually a rare condition, affecting an estimated 0.6 percent of males worldwide. But what appears to be a small penis may not technically qualify as a micropenis. It may instead be a condition known as buried penis.

Buried penis

A buried penis is a penis of normal size, but it is hidden or buried under folds of skin of the abdomen, thigh, or scrotum. A buried penis is usually diagnosed in infancy, but it can develop later in life.

The condition may be caused by an abnormality that a boy is born with or it may be due to the buildup of fat in the abdomen and around the genitals in someone with morbid obesity.

As men age, their pelvic floor muscles tend to weaken. This affects how the penis rests and it affects erectile function. Weaker muscles can allow the penis to recede somewhat, leading to a buried penis appearance in some men.

Healthy pelvic floor muscles also contract when a man has an erection, helping to ensure proper blood flow in the penis. Weaker muscles allow blood to escape, making it difficult to maintain an erection.

Webbed penis

Another condition that may be mistaken for micropenis is webbed penis, also known as an “inconspicuous penis.” A baby boy can be born with it or it can develop from a circumcision complication.

With a webbed penis, skin from the scrotum is attached unusually high on the shaft of the penis. The result is that the penis itself looks smaller than normal because just the tip and some of the shaft is visible.

Cosmetic surgery can correct the problem, but that usually is delayed until a boy reaches his teens or adulthood.

Talking with endocrinologists, urologists, and surgeons about treatment options will also help you understand what your options are at any age.

Treating micropenis can be helpful in boosting self-confidence later in life and improving the chances of satisfying sexual activity.

Treatment that begins earlier in life can lead to better results. Your child’s age, medical history, and the extent of the condition will help determine what treatment options make the most sense.

Hormone therapy

Hormone therapy can often be done starting at an early age. It may help stimulate penile growth. It begins with a short course of testosterone treatments to see how the penis responds. The hormone can be delivered through an injection or through a gel or ointment applied directly to the penis.

Testosterone therapy may help stimulate penile growth in infancy, though there is less evidence that it is effective in puberty and adulthood. Other types of hormone treatment may be tried if testosterone is ineffective.


Surgery to correct micropenis, a procedure called phalloplasty, is more common in adolescents and adults than in infants and young children. It is usually done if hormone treatments have been ineffective. However, the surgery can be done at a young age.

There are risks, as with any type of surgery. Complications affecting the urinary tract, erectile function, and other function may occur, and may require subsequent procedures. Some also argue that resulting changes to size or length are not significant enough to outweigh risks.

Still, advances in plastic surgerymean that for many boys and men, a surgically modified penis that allows for healthy urinary and sexual function is possible. It is important to work with an experienced surgeon and understand all of the potential risks and benefits of surgery.

Accepting your body

In the media and in society generally, penis size is often mistakenly equated with manliness. In an intimate relationship, having a micropenis can require adjustments and healthy attitudes by both partners.

Providing some counseling at an early age may help a boy cope better as he ages and equip him with strategies to deal with peers and potential partners and achieve a rewarding quality of life.

Therapists along with medical doctors are available for you, regardless of your age, to give guidance during important aspects of dealing with life — emotional, sexual, and biological.

Micropenis has specific medical definition and measurement. Living with a micropenis can be a challenge that may require psychological counseling to help you adjust, whether you want to seek medical treatment or not.

Researching and discussing treatment options with health professionals may lead to positive outcomes.