What Is Diphallia?

Diphallia is a rare condition where someone is born with two penises. The condition was first identified in 1609 and, since then, only about 100 cases have been recorded. Diphallia is extremely uncommon, affecting roughly one out of every 5-6 million babies born.

Experts aren’t sure what causes diphallia. What is known is that it's a congenital condition, meaning it occurs before birth.

By itself, having two penises is not dangerous. However, people with diphallia often have other abnormalities that can be more serious. This can include having more than one bladder, urethra, or colon, as well as malformation of the anus, rectum, and vertebrae.

Treatment for diphallia isn’t always necessary. If treatment occurs, it usually involves surgery.

Diphallia Symptoms

People who have diphallia will have symptoms as soon as they are born. Each person with this condition will have genitals that look different—no two cases of diphallia are exactly alike.

Physical Characteristics of Diphallia

Each case of diphallia looks a little different. Some people have small amounts of extra penile tissue, while other people have two complete penises. When a person has two complete penises, they are not usually of equal size. The penises may lie side by side or be stacked on top of each other.

People who have diphallia often have other abnormalities, usually of the urinary, digestive, or reproductive system. The most common abnormality is an imperforate anus, which is when the anus is blocked or absent. Some people might also have duplicate bladders and urethras (the tube that lets urine and semen leave the body).

Functionality

Some people have two fully functional penises with working urethras. They may be able to urinate and ejaculate out of both penises. Other people have only one working penis, with the other not having a urethra, scrotum, or testes. Sometimes both penises can become erect, but other times only one is capable of erection.

What Causes Diphallia?

The precise cause of diphallia is unclear. Diphallia happens before birth and may occur during either the embryonic or fetal stage of development.

Some researchers have hypothesized the condition occurs during the third to sixth week of pregnancy, when the penis begins to develop. Other researchers have theorized diphallia occurs at different points of penile, genital, or urinary development, such as between weeks 23-25 of pregnancy.

It's not known why diphallia occurs in pregnancy, though some researchers believe environmental factors may be at play, including drug usage or maternal infections. Additionally, researchers have suggested that chromosomal abnormalities may play a role in the development of diphallia.

How Is Diphallia Diagnosed?

Diphallia is usually diagnosed soon after birth based on physical observations. Sometimes a healthcare provider will want to do some further testing to see if other internal organs have complications or abnormalities since diphallia can be associated with malformations of the urethra, bladder, and various digestive and reproductive organs.

A healthcare provider may use ultrasounds to confirm the diagnosis. At times, a magnetic resonance imaging (MRI) scan may needed for more detailed images and to help guide possible treatment.

Treatments for Diphallia

The goal of treatment is to preserve functionality of the penis in terms of urination and reproductive function and to address any cosmetic concerns.

There isn’t one uniform treatment protocol for diphallia since each cases is distinct. Treatment will depend on the appearance and function of the penis and associated reproductive organs. Treatment will also depend on what other organs are affected, which may include the urethra, bladder, anus, and rectum.

If treatment for diphallia is decided upon, it usually involves surgery. The surgery performed will be specific to the case and any complications present. Surgery may involve the removal of penile tissue or a second non-functioning penis, penis reconstruction, or reconstruction of the urethra.

How To Prevent Diphallia

Because the causes of diphallia are unknown, it’s not possible to prevent the condition. Some experts theorize diphallia may be caused by environmental factors like drug usage or exposure to infections, so practicing fetus-safe habits and receiving prenatal care throughout your pregnancy may be helpful. Keep in mind these preventative steps have not been proven and that diphallia is rare.

Related Conditions

Some people who have diphallia have no other abnormalities. But many people who have diphallia will have other congenital conditions or malformations. These abnormalities are usually in the genital area, urinary system, or gastrointestinal system. Less commonly, abnormalities are present in the muscular, skeletal, or cardiovascular system.

The majority of abnormalities and malformation are either genitourinary (involving genitals and urinary organs) or gastrointestinal.

Related genitourinary conditions include:

• The presence of two bladders
• The presence of two ureters
• Bladder exstrophy, where the bladder develops outside of the fetus
• Vesicoureteral reflux, where urine flows back to the bladder
• Ureteric stenosis, which is narrowing of the ureters
• Malformation of the kidneys
• Fistulas (abnormal connections) in the urinary system

Related gastrointestinal abnormalities include:

• Imperforate anus, where the anal opening is missing or blocked
• The presence of two rectums, colons, appendixes, ileums, or cecums
• A higher likelihood of developing hernias, which are sacs of tissue that push through a hole or weak area
• Bowel segments that are abnormally placed or positioned
• Omphalocele, a birth defect in the abdominal wall
• Meckel diverticulum, a bulge in the lower intestine

Possible musculoskeletal abnormalities include:

• Hemivertebra, where only one side of the spine develops correctly
• Separation (diastasis) of the pubic bone
• Menigocele, a type of spina bifida
• Talipes equinovarus (club foot)

Although rare, cardiovascular-related abnormalities may include atrial septal defects, which is when there is a hole in the wall separating your heart’s upper chambers.

Living With Diphallia

If you have a baby with diphallia or if you are living with the condition, you may have many questions and concerns. On its own, diphallia is not harmful to your physical health, but if it is accompanied by other related abnormalities or if it causes your organs to not function properly, complications can arise. Each case of diphallia is unique and requires different treatment and management. It’s important to be in touch with your or your child's medical team as you navigate living with diphallia.

Diphalia can also impact interpersonal and sexual relationships, which can affect your mental health. You can ask your healthcare provider for a referral to a mental health specialist if diphalia is impacting your emotional health and well-being.