Ambiguous genitalia is a rare condition in which an infant's external genitals don't appear to be clearly either male or female. In a baby with ambiguous genitalia, the genitals may be incompletely developed or the baby may have characteristics of both sexes. The external sex organs may not match the internal sex organs or genetic sex.

Ambiguous genitalia isn't a disease, it's a disorder of sex development. Usually, ambiguous genitalia is obvious at or shortly after birth, and it can be very distressing for families. Your medical team will look for the cause of ambiguous genitalia and provide information and counseling that can help guide decisions about your baby's gender and any necessary treatment.

Your medical team will likely be the first to recognize ambiguous genitalia soon after your baby is born. Occasionally, ambiguous genitalia may be suspected before birth (prenatally). Characteristics can vary in severity, depending on when during genital development the problem occurred and the cause of the disorder.

Babies who are genetically female (with two X chromosomes) may have:

• An enlarged clitoris, which may resemble a penis
• Closed labia, or labia that include folds and resemble a scrotum
• Lumps that feel like testes in the fused labia

Babies who are genetically male (with one X and one Y chromosome) may have:

• A condition in which the narrow tube that carries urine and semen (urethra) doesn't fully extend to the tip of the penis (hypospadias)
• An abnormally small penis with the urethral opening closer to the scrotum
• The absence of one or both testicles in what appears to be the scrotum
• Undescended testicles and an empty scrotum that has the appearance of a labia with or without a micropenis

Ambiguous genitalia primarily occurs when hormone abnormalities during pregnancy interrupt or disturb the fetus's developing sex organs.

How sex organs form in the womb

A baby's genetic sex is established at conception, based on the sex chromosomes. The mother's egg contains an X chromosome, and the father's sperm contains either an X or a Y chromosome. A baby who inherits the X chromosome from the father is a genetic female (two X chromosomes). A baby who inherits the Y chromosome from the father is a genetic male (one X and one Y chromosome).

Male and female sex organs develop from the same tissue. Whether this tissue becomes male organs or female organs depends on the chromosomes and the presence or absence of male hormones.

• In males, a region on the Y chromosome triggers the development of testicles, which produce male hormones. Male genitals develop in response to male hormones from the fetal testicles.
• In a fetus without a Y chromosome — without the effects of male hormones — the genitals develop as female.

Occasionally, a chromosomal abnormality may make determination of genetic sex complex.

How ambiguous genitalia occurs

A disruption of the steps that determine sex can result in a mismatch between the appearance of the external genitals and the internal sex organs or the genetic sex (XX or XY).

• A lack or deficiency of male hormones in a genetic male fetus can cause ambiguous genitalia, while exposure to male hormones during development results in ambiguous genitalia in a genetic female.
• Mutations in certain genes can influence fetal sex development and cause ambiguous genitalia.
• Chromosomal abnormalities, such as a missing sex chromosome or an extra one, also can cause ambiguous genitalia.
• In some cases, the cause of ambiguous genitalia may not be determined.

Possible causes in genetic females

Causes of ambiguous genitalia in a genetic female may include:

• Congenital adrenal hyperplasia. Certain forms of this genetic condition cause the adrenal glands to make excess male hormones (androgens).
• Prenatal exposure to male hormones. Certain drugs that contain male hormones or that stimulate production of male hormones in a pregnant woman can cause developing female genitals to become more masculine. A developing baby also may be exposed to excess male hormones if the mother has a disease or condition that causes hormone imbalance.
• Tumors. Rarely, a tumor in the mother can produce male hormones.

Possible causes in genetic males

Causes of ambiguous genitalia in a genetic male may include:

• Impaired testicle development. This may be due to genetic abnormalities or unknown causes.
• Androgen insensitivity syndrome. In this condition, developing genital tissues don't respond normally to male hormones made by the testes.
• Abnormalities with testes or testosterone. Various abnormalities can interfere with the testes' activity. This may include structural problems with the testes, problems with production of the male hormone testosterone or problems with cellular receptors that respond to testosterone.
• 5a-reductase deficiency. This enzyme defect impairs normal male hormone production.

Ambiguous genitalia can also be a feature of certain rare, complex syndromes that affect many organ systems.

Family history may play a role in the development of ambiguous genitalia, because many disorders of sex development result from genetic abnormalities that can be inherited. Possible risk factors for ambiguous genitalia include a family history of:

• Unexplained deaths in early infancy
• Infertility, absent menstrual periods or excess facial hair in females
• Genital abnormalities
• Abnormal physical development during puberty
• Congenital adrenal hyperplasia, a group of inherited genetic disorders that affect the adrenal glands

If your family has a history of these risk factors, consider seeking medical advice before trying to conceive. You may also benefit from genetic counseling.

Complications of ambiguous genitalia may include:

• Infertility. Whether people with ambiguous genitalia can have children depends on the specific diagnosis. For example, genetic females with congenital adrenal hyperplasia usually can get pregnant if they so choose.
• Increased risk of certain cancers. Some disorders of sex development are associated with an increased risk of certain types of cancer.

Ambiguous genitalia is usually diagnosed at birth or shortly after. Doctors and nurses who help with delivery may notice the signs of ambiguous genitalia in your newborn.

Determining the cause

If your baby is born with ambiguous genitalia, the doctors will work to determine the underlying cause. The cause helps guide treatment and decisions about your baby's gender. Your doctor will likely begin by asking questions about your family and medical history. He or she will do a physical exam to check for testes and evaluate your baby's genitalia.

Your medical team will likely recommend these tests:

• Blood tests to measure hormone levels
• Blood tests to analyze chromosomes and determine the genetic sex (XX or XY) or tests for single gene disorders
• Ultrasound of the pelvis and abdomen to check for undescended testes, uterus or vagina
• X-ray studies using a contrast dye to help clarify anatomy

In certain cases, minimally invasive surgery may be necessary to collect a tissue sample of your newborn's reproductive organs.

Determining the gender

Using the information gathered from these tests, your doctor may suggest a gender for your baby. The suggestion will be based on the cause, genetic sex, anatomy, future reproductive and sexual potential, probable adult gender identity, and discussion with you.

In some cases, a family may make a decision within a few days after the birth. However, it's important that the family wait until test results are completed. Sometimes gender assignment can be complex and the long-term impact can be difficult to predict. Parents should be aware that as the child grows up, he or she may make a different decision about gender identification.

Once you and your doctor have chosen a gender for your baby, you may choose to begin treatment for ambiguous genitalia. The goal of treatment is long-term psychological and social well-being, as well as to enable sexual function and fertility to the greatest extent possible. When to begin treatment depends on your child's specific situation.

Ambiguous genitalia is uncommon and complex, and it may require a team of experts. The team might include a pediatrician, neonatologist, pediatric urologist, pediatric general surgeon, endocrinologist, geneticist, and psychologist or social worker.

Medications

Hormone medications may help correct or compensate for the hormonal imbalance. For example, in a genetic female with a slightly enlarged clitoris caused by a minor to moderate case of congenital adrenal hyperplasia, proper levels of hormones may reduce the size of the tissue. Other children may take hormones around the time they would normally experience puberty.

Surgery

In children with ambiguous genitalia, surgery may be used to:

• Preserve normal sexual function
• Create genitals that appear more typical

The timing of surgery will depend on your child's specific situation. Some doctors prefer to postpone surgery done solely for cosmetic reasons until the person with ambiguous genitalia is mature enough to participate in the decision about gender assignment.

For girls with ambiguous genitalia, the sex organs may work normally despite the ambiguous outward appearance. If a girl's vagina is hidden under her skin, surgery in childhood can help with sexual function later. For boys, surgery to reconstruct an incomplete penis may normalize appearance and make erections possible. Surgery to reposition the testes into the scrotum may be required.

Results of surgery are often satisfying, but repeat surgeries may be needed later. Risks include a disappointing cosmetic result or sexual dysfunction, such as an impaired ability to achieve orgasm.

Ongoing care

Children with ambiguous genitalia require ongoing medical care and monitoring for complications, such as cancer screenings, into adulthood.

If your baby is diagnosed with ambiguous genitalia, you may worry about your child's future. Mental health professionals can help you deal with this difficult and unexpected challenge. Ask your child's doctor for a referral to a mental health professional who has experience helping people in your situation.

In addition to ongoing counseling for your family and your child, you may benefit from a support group, either in person or online. Your child can benefit from ongoing counseling by mental health professionals and participation in support groups into adulthood.

Not knowing the gender of your newborn immediately can turn a hoped-for celebration into a stressful crisis. Your medical team will provide you with updates and information as quickly as possible to help settle any questions about your child's health.

Consider delaying a formal announcement of the birth until testing is complete and you've developed a plan with advice from your medical team. Give yourself some time to learn and think about the issue before answering difficult questions from family and friends.

If your baby was born with ambiguous genitalia, you may be referred to a medical center with doctors who have expertise in this condition. Here's some information to help you get ready for your appointment and learn what to expect from your doctor.

What you can do

Before your appointment:

• Ask if there's anything you need to do in advance to prepare your infant for tests and procedures.
• Discuss family history with your relatives and bring key personal information, including family history of genetic diseases or conditions, such as ambiguous genitalia.
• Consider taking a family member or friend along. Sometimes it can be difficult to remember all the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot.
• Make a list of questions to ask your doctor.

Questions to ask your doctor may include:

• What caused my baby's uncertain genitalia?
• What genetic testing has been completed?
• What other tests might my baby need?
• What is the best course of action?
• What are the alternatives to the primary approach that you're suggesting?
• Is there a generic alternative to the medicine you're prescribing?
• Are there any restrictions that my baby needs to follow?
• Should my baby see any other specialists?
• What options are there for counseling and support for our family?
• Are there brochures or other printed materials that I can have? What websites do you recommend?

Don't hesitate to ask other questions during your appointment.

What to expect from your doctor

Your doctor is likely to ask you several questions, such as:

• Does your family have a history of ambiguous genitalia?
• Does your family have a history of other genetic diseases?
• Do any diseases or conditions tend to run in your family?
• Have you ever had a miscarriage?
• Have you ever had a child who died in infancy?

Be ready to answer questions to allow more time to cover other points you want to address.