What Is A Micropenis – And How Does It Affect Sex?

Many people are concerned about their penis size being too small. However, only a fraction of people with small penises actually has a micropenis. 

A micropenis is a rare medical condition where genetics or hormonal issues cause a small penis that is well under the average size. For a penis to be considered a micropenis, a penis has to be 2.5 standard deviations below the average stretched penis size for their age. 

"Anything less than around 3.65 inches when stretched or erect can be considered 'micropenis,'" Jamin Brahmbhatt, MD, a urology and sexual health expert at Orlando Health, told Health. Other researchers consider an adult micropenis length anything under 3.67 inches.

Typically, micropenis is diagnosed in newborn babies. It's not a condition that causes a normal-size member to suddenly shrink. "You can’t develop micropenis over time," Brahmbhatt said.

As an adult, having a micropenis may leave people feeling self-conscious, especially during sex. However, if you or your partner have a micropenis, you can still have sex and lasting relationships.

Here are some things to know about micropenis — from why it happens to how it affects sex.

What Causes a Micropenis?


A micropenis is likely caused by hormonal abnormalities while a baby grows in the womb. “At this stage, low testosterone production can prevent a fetus' penis from developing normally,” Arash Akhavein, MD, a urologist at Comprehensive Urology in Los Angeles, told Health.

Other medical conditions and genetic disorders can also cause a micropenis:

  • Hypogonadotropic hypogonadism: This is a condition that affects testosterone levels, and can prevent usual penis growth.
  • Rare genetic disorders: Genetic disorders like Kallman's syndrome can also delay or prevent puberty, often resulting in a micropenis.
  • Disorder of sex development (DSD): This is a chromosomal disorder that can cause micropenis.

Research has also linked micropenis to pesticide exposure during pregnancy and taking estrogen-based fertility drugs in early pregnancy. Sometimes, though, healthcare providers can't pinpoint exactly what causes a micropenis.

Micropenis Symptoms and Diagnosis

The main symptom of a micropenis is its small size, which depends on your age. Adults with a micropenis will have a stretched penis length of 9.32 centimeters (3.67 inches) or less.

The testicles and other internal genitalia are usually still average size. That being said, it is possible to have a micropenis and small or underdeveloped testicles.

Healthcare providers usually diagnose micropenis in newborn babies by measuring a stretched penis from the pubic bone to the tip of the head of the penis. In babies, a micropenis is a stretched penis length of fewer than 1.9 centimeters (.75 inches). 

Children who have not hit puberty can also be diagnosed with micropenis if their stretched penis length is 3.8 centimeters (1.5 inches) or shorter.

To determine what causes a person's micropenis, a healthcare provider may also check for genetic or hormonal abnormalities using blood tests.

When Is a Small Penis Not a Micropenis? 

"True micropenis is reported to be present in 1.5 in 10,000 born male children," said Dr. Akhavein. 

Penises come in all shapes and sizes. Having a smaller-than-average penis doesn’t necessarily mean you have a medical condition, and size isn’t the most important part of having sex.  

However, some conditions can make a person's penis look small and even be mistaken for a micropenis:

  • Buried penis: Penises that appear hidden within folds of fat can make the penis look smaller than it actually is. 
  • Webbed penis: People with extra skin connecting the scrotum and penis can also appear to have a smaller penis. 
  • Trapped penis: This is a circumcision complication that can make the penis hide behind dense scar tissue.

Micropenis Treatment Options

A micropenis can often be treated with testosterone therapy if diagnosed in infancy. "Sometimes you can give [an infant with a micropenis] a ton of testosterone in the first three months of life and get the penis to grow," Audrey Rhee, MD, a urologist at the Cleveland Clinic, told Health. Testosterone treatment can still be effective even after infancy, but only if it's done before puberty.

Testosterone therapy often involves a series of testosterone shots, but infants can also have testosterone cream applied to the skin. Research shows both treatments are effective at accelerating penis growth in babies and young children. The treatments have minimal side effects, but can also increase overall growth rate and bone growth.

Surgery to elongate the penis, known as phalloplasty, is another option for adults. However, surgical options can cause complications and don't offer significant results. 

One type of phalloplasty, known as a suspensory ligament release, detaches the ligament that supports the penis during erection. This can give the illusion of a larger penis, but the surgery can cause risks like nerve damage, erectile dysfunction, or loss of sensation. You may also develop scar tissue that can make the penis retract and appear smaller.

Other types of phalloplasty use tissues from other body sites (for example, the forearm muscle flaps) to create a new penis (and urethra), said Dr. Akhavein. This surgery is also extremely risky. 

What Is Sex Like With a Micropenis?

Having a micropenis does not generally prevent people with penises from getting erections, masturbating, having orgasms, or urinating, said Dr. Brahmbhatt. However, sometimes a person with a micropenis will be unable to have penetrative sex, added Dr. Akhavein.

But it is possible to have a fully satisfying sex life if you or your partner have a micropenis. Just focus on the sex acts you can perform. "You can have a whole lot of fun and satisfaction from fingers, mouths, and toys," Kait Scalisi, MPH, a sex educator, told Health. "Strap-ons and penis extenders augment your body. Vibrators stimulate the most sensitive part of the genitals, whether that's the clitoris, G-spot, prostate, or frenulum."

Scalisi also suggested experimenting with positions, such as variations of missionary where the receptive partner props their hips on a stack of pillows and then places their legs straight up to rest on the partner's chest and shoulders, while the penetrative partner kneels. Doggy style is another great option, as larger penises can cause discomfort or pain.

Does a Micropenis Affect Fertility? 

Having a micropenis doesn't necessarily make you infertile, but it can make conception more challenging. Some research has linked penis lengths less than 2 inches to lower conception rates. If a person has a pituitary disorder that causes micropenis, low testosterone levels may also cause low sperm count.

If assisted reproduction technology, like intrauterine insemination (IUI) or in vitro fertilization (IVF), can help you and a partner conceive a child, especially if penetrative sex is not possible. 

A Quick Review

Micropenis is a medical condition where genetics or hormonal issues make a person's penis significantly smaller than the average length. Micropenis can often be treated if diagnosed early on in babies or children. But it can be difficult to treat after puberty and into adulthood. 

If you have a micropenis, you and your partner can often still enjoy penetrative sex. But if penetration isn't possible, exploring other sex acts with your partner can help you both find satisfaction. 

If you struggle to accept your body, talking with a therapist can help you find emotional support and form strategies to help you navigate sexual relationships. If you're concerned about your penis size, shape, or function, talk with your healthcare provider. 

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