A newborn's genitalia are quite small, and the idea of looking "normal" spans a wide range. Your medical team will likely be the first to recognize the signs of ambiguous genitalia soon after your baby is born. These signs vary from the more obviously apparent to the outwardly invisible.

Characteristics in genetic females
For genetic females, the baby's genitals may take on the following characteristics:

• An enlargement of the clitoris, or what appears to be a small penis
• A concealment of the vagina because the midline groove has closed over

Characteristics in genetic males
For genetic males, the following characteristics may be present:

• Hypospadias — a condition in which the narrow tube that carries urine and semen (urethra) doesn't fully extend to the tip of the penis
• An abnormally small penis with the urethral opening nearer to the scrotum, indicating that the penis stopped growing early in its development
• No recognizable male genitalia in the most severe cases
• The absence of both testicles in what appears to be the scrotum

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

The role of chromosomes
The genetic sex of a child is established at conception based on the 23rd pair of chromosomes it inherits. The mother's egg contains an X chromosome, and the father's sperm contains either an X or Y chromosome. A baby who inherits the X chromosome from the father is a genetic female (a pair of X chromosomes). A baby who inherits the Y chromosome from the father is a genetic male (one X and one Y chromosome).

Fetal sexual development
In early fetal development, males and females are indistinguishable. Male and female sex organs develop from the same tissue in the fetus. For example, the same fetal tissue that forms a penis in a male also forms a clitoris in a female. The presence or absence of male hormones controls the development of the sex organs. Normally, male genitalia develop because of male hormones from the fetal testicles. In the female fetus — without the effects of male hormones — the genitalia develop as female.

A deficiency of male hormone in a genetic male fetus results in ambiguous genitalia. In a female fetus, the presence of male hormone during development results in ambiguous genitalia. Although the deficiency or presence of male hormones is the main factor controlling genital development, the exact cause of ambiguous genitalia is often unknown. Many of the disorders seem to happen by chance.

Possible causes in genetic females
Causes of ambiguous genitalia in a genetic female may include:

• Congenital adrenal hyperplasia (CAH). Certain forms of this genetic condition cause the adrenal glands to make excess male hormones (androgens). Congenital adrenal hyperplasia is the most common cause of ambiguous genitalia in newborns.
• Ingestion by the mother of substances with male hormone activity, such as progesterone (taken in the early stages of pregnancy to stop bleeding).
• Tumors in the fetus or the mother that produce male hormones.

Possible causes in genetic males
Causes of ambiguous genitalia in a genetic male may include:

• Impaired testicle development due to genetic abnormalities or unknown causes.
• Leydig cell aplasia, a condition that impairs testosterone production.
• Congenital adrenal hyperplasia. Certain forms of this genetic condition can impair production of male hormones.
• Androgen insensitivity syndrome, a condition in which developing genital tissues are unable to respond to normal male hormone levels.
• 5alpha-reductase deficiency, an enzyme defect that impairs normal male hormone production.
• Ingestion by the mother of substances with female hormone activity, such as estrogens, or anti-androgens. This is unusual, but could occur if a woman taking birth control pills gets pregnant despite taking the pills — then, not knowing she's pregnant, continues taking the pills into pregnancy for several weeks. Also some "nutritional supplements" contain plant estrogens.

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As is the case with many abnormalities, family history may play a role in the development of ambiguous genitalia. Possible risk factors associated with ambiguous genitalia include a family history of:

• Unexplained deaths in early infancy
• Infertility in close relatives
• Genital abnormalities
• Abnormal development during puberty

Because most causes of ambiguous genitalia are due to genetic abnormalities, the presence of similar abnormalities in family members is important. Having a family member with known congenital adrenal hyperplasia, infertility or abnormal pubertal development may indicate a genetic abnormality in the family. Also, a personal or family history of prior babies being born with genital abnormalities, or dying shortly after birth, may indicate an inherited abnormality that could result in future children being born with ambiguous genitalia.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

If both parents are carriers of congenital adrenal hyperplasia, there's the chance that their baby could develop ambiguous genitalia if he or she inherits the abnormal gene from both parents. Parents may not know they have congenital adrenal hyperplasia because as carriers they show no signs or symptoms of this condition.

If your family has a history of risk factors associated with ambiguous genitalia, seek medical advice before conceiving.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

If your baby is born with ambiguous genitalia, you and your doctor will want to determine the underlying abnormality and extent of deformity. The first indication of ambiguous genitalia will be by a physical examination. Your doctor will likely recommend the following tests and procedures:

• Blood and urine tests to measure hormone levels
• Chromosome analysis to determine the genetic sex (XX or XY)
• Ultrasound to check for the presence of internal female sex organs
• A biopsy of your newborn's reproductive organs to determine if the organs will produce appropriate sex hormones for the sex assigned to the child
• A genitogram, a special X-ray to see if a vagina is present and its size

Using the information gathered from these tests, your doctor may suggest an appropriate sex for the baby.

Despite the social stigma attached to not knowing if your baby is a boy or a girl right away, some research shows that delaying gender assignment until the child is older may be of benefit. If the gender assignment is made too early, and the correct decision isn't made, your child may be confronted with difficult psychological and social issues later in life.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

The outlook is good for many babies born with ambiguous genitalia in terms of their ability to conceive and be fertile later in life. However, for others born with ambiguous genitalia, the severity of the condition, complicated hormone levels and trouble adjusting to their assigned sex may make it difficult or impossible to conceive a child later in life.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

Management of ambiguous genitalia requires a team of doctors that may involve a number of specialties — pediatric endocrinology, neonatology, urology, plastic surgery, medical genetics and psychology. Your medical team can explain to you the options available for your child and likely suggest a course of action. The timing of treatment depends on a child's specific situation.

Treatment options may include:

• Reconstructive surgery. The goal of surgery is usually cosmetic, to make the boy's or girl's genitalia look natural. In some cases, the surgery can be more involved in hopes of restoring sexual function. Results are often satisfying. However, your child may need repeat surgeries later in life. And there is a risk of a disappointing cosmetic result or sexual dysfunction, such as an inability to achieve orgasm.

  Certain types of surgery for ambiguous genitalia are most successful when carried out soon after birth, while others are best delayed until later in your child's development — in some cases, until your child reaches sexual maturity. In severe cases of ambiguous genitalia, both the medical and psychological results may be better if surgery is delayed until your child can play a role in participating in the sex-assignment decision.

  For girls, sexual function of the organs is often not compromised despite any ambiguous appearance. Depending on the severity of the condition, surgery options range from uncovering a vagina hidden under the skin to removing excess masculine tissue around the clitoris. Surgeries are carried out carefully to avoid damaging nerve endings and blood flow in hopes of ensuring normal sexual function in the future.

  For boys, the surgery may be more complicated, but often successful. Surgery gives genetic males born with a shorter, incomplete penis the opportunity to have a more normal penis. In many cases, no further surgery is required for this reconstructed organ, and it will have a normal look and erectile functionality. Female organs that remain under the skin — such as a uterus or vagina — rarely cause a physical problem, but are often surgically removed because a boy's knowledge of these structures later in life may be emotionally difficult.

• Hormone therapy. Depending on the severity of the condition, hormone therapy alone may be enough to correct the initial 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 shrink the tissue close to a normal size.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

Not knowing the sex of your baby immediately is a difficult issue to face. As parents, it's best to discipline your thoughts not to think of your baby as a girl or a boy until a medical evaluation is complete.

Meanwhile you might consider giving the child a neutral name suitable for either a boy or a girl. You might also defer announcing the birth until the evaluations are complete in that the first question everyone asks regarding a new baby is whether it's a girl or a boy.

Because of the additional stress this may place on a family, ongoing counseling for the child as well as the family may become an important part of the process. Mental health providers and support groups may all help you to deal with this difficult and unexpected set of circumstances.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.