Micropenis is an atypically small penis that’s discovered in infancy or very early childhood. It’s usually the result of a fetal testosterone deficiency. In some people, early hormonal treatment may help stimulate growth of the penis toward a more normal length.


What is a micropenis?

Micropenis is a medical term for a small but normally structured penis. Hormonal or genetic factors can cause this condition. Healthcare providers often note the condition during the newborn to early childhood period.

As long as no other health concerns are present, a micropenis can function normally. People with micropenis are still able to urinate (pee) and have erections.


Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

How many people have a micropenis?

Micropenis is very rare, affecting about 0.6% of people worldwide. In the United States, approximately 1.5 in 10,000 newborns are born with micropenises.

What size is a micropenis?

Healthcare providers determine micropenis size by the stretched penile length (SPL). The proper way to establish the SPL is to gently stretch the penis, hold it close to the body and measure it from tip to base of the penis. Providers diagnose micropenis if the length is less than 2.5 standard deviations below the average. For example:

  • The average stretched penile length (SPL) for adult males is 5.25 inches. An SPL of 3.67 inches or less indicates an adult micropenis.
  • The average SPL for a newborn is 1.4 inches. An SPL of 0.75 inches or less indicates an infant micropenis.

Symptoms and Causes

What are the symptoms of a micropenis?

The most common micropenis symptom in babies is a penis that measures less than 0.75 inches when gently stretched. In adults, a penis that measures 3.67 inches or less when gently stretched is a micropenis.

Micropenis can occur on its own, but it often accompanies other health problems due to hormonal disorders or congenital (present at birth) conditions. Your child’s symptoms will depend on the cause of the micropenis.

Some people with micropenises may have a lower sperm count, but this isn’t always the case.

What causes a micropenis?

Micropenis is usually caused by fetal testosterone deficiency, which can be the result of a variety of conditions, including Prader-Willi syndrome, Kallman syndrome or, most commonly, hypogonadotropic hypogonadism.

Hypogonadotropic hypogonadism occurs when your hypothalamus (the part of your brain that controls your autonomous nervous system and pituitary gland) doesn’t secrete the hormones that stimulate your testicles to produce testosterone. This process is necessary for normal maturation and reproductive function.

Sometimes, there’s no known cause for micropenis.


Diagnosis and Tests

How is a micropenis diagnosed?

Your healthcare provider can diagnose micropenis with a physical examination. They’ll gently stretch your penis and measure it. The number is then compared to the size range of your particular age group.

Management and Treatment

How is a micropenis treated?

The most common micropenis treatments include testosterone therapy and surgery.

People of all ages can benefit from micropenis treatment. But the chances of success are greater if a healthcare provider diagnoses and treats the condition in infancy.

If your baby has a micropenis, your healthcare provider may refer you to a pediatric urologist or endocrinologist.

Testosterone therapy for micropenis

The first line of treatment is usually a short course of testosterone. This therapy tests the ability of the penis to respond to the growth hormone.

Your healthcare provider may recommend testosterone injections or testosterone skin gel. Studies show that penile growth is good with testosterone treatment in many infants, but whether the growth continues during puberty and adulthood isn’t known. You shouldn’t try testosterone injections or skin gels unless they’re prescribed by your healthcare provider.

Your healthcare provider may try other treatments if testosterone therapy doesn’t add length to the penis.

Micropenis surgery

If you’re an adult considering micropenis surgery, make sure you clearly understand the risks and benefits of your particular situation.

How long does it take to recover from micropenis surgery?

Recovery time after micropenis surgery depends on several factors, such as your health history and your body’s healing capacity. Most people can return to work, school and other normal routines in about four to six weeks. If your job requires physical exertion, you’ll probably need to wait six to eight weeks.

Outlook / Prognosis

What can I expect if I have a micropenis?

The outlook for people with micropenis varies depending on the cause. For example, people who have micropenis due to hormone deficiency typically have a good outlook, especially with early diagnosis and treatment. They usually respond well to testosterone therapy at a younger age, gain adequate penile length and are able to function normally as adults.

Other disorders, such as androgen insensitivity syndrome, are sometimes more challenging to treat. Hormone treatment doesn’t work for these individuals. In these cases, their penis may remain small.

Living With

How do people cope with having a micropenis?

If early treatment is unsuccessful for a micropenis, coping with the condition can be difficult.

In all cases, psychological counseling and social services will be helpful in maintaining good mental and emotional health.

Micropenis is a rare condition — and how you treat it depends on many factors. Your healthcare provider will talk with you about your options every step of the way.

Does having a micropenis have a negative impact on sexual function?

Most people with a micropenis function normally when it comes to sex. A micropenis doesn’t affect your ability to pee, masturbate or reach orgasm.

Micropenis doesn’t have to be a barrier to sex or intimacy. If you find that penetration is difficult, you can explore other ways to enjoy sex with a partner. Talk to a counselor or sex therapist about overcoming anxiety regarding penis size.

When should I see my healthcare provider?

If your baby has micropenis, you should call their healthcare provider if any new symptoms develop.

If you’re an adult concerned about micropenis, talk to your healthcare provider. They can refer you to a urologist.

A note from Cleveland Clinic

If your child has micropenis — or if you’re concerned about your own penis size — your healthcare provider can talk with you about treatment options. They can also refer you to a counselor or therapist who can help you overcome any anxieties associated with micropenis.

In society, penis size is often falsely equated with masculinity. As a result, those with micropenis might feel embarrassed or self-conscious. But it’s important to understand that penis size has nothing to do with masculinity. People with smaller-than-average penises still lead healthy, sexually active lives.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 09/06/2022.

Learn more about our editorial process.

Urology 216.444.5600
Kidney Medicine 216.444.6771