The genetic sex of a child is determined at conception. The mother's egg cell (ovum) contains an X chromosome, while the father's sperm cell contains either an X or a Y chromosome. These X and Y chromosomes determine the child's genetic sex. Normally, an infant inherits ONE PAIR of sex chromosomes -- one X from the mother and one X or one Y from the father. Thus, it is the father who "determines" the genetic sex of the child. 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).

The male and female reproductive organs and genitals both arise from the same tissue in the fetus. If the process that causes this fetal tissue to become "male" or "female" is disrupted, ambiguous genitalia can develop.

Ambiguous genitalia are those in which it is difficult to classify the infant as male or female. The extent of the ambiguity varies. In very rare instances, the physical appearance may be fully developed as the opposite of the genetic sex (e.g., a genetic male may have developed the appearance of a normal female).

Typically, ambiguous genitalia in genetic females (babies with two X chromosomes) include an enlarged clitoris that has the appearance of a small penis. The urethral opening (where urine comes out) can be anywhere along, above, or below the surface of the clitoris. The labia may be fused, resembling a scrotum. The infant may be thought to be a male with undescended testicles. Sometimes a lump of tissue is felt within the fused labia, further making it look like a scrotum with testicles.

In a genetic male (one X and one Y chromosome), ambiguous genitalia typically include a small penis (less than 2-3 centimeters or 0.8-1.2 inches) that may appear to be an enlarged clitoris (the clitoris of a newborn female is normally somewhat enlarged at birth). The urethral opening may be anywhere along, above, or below the penis; it can be placed as low as on the peritoneum, further making the infant appear to be female. There may be a small scrotum with any degree of separation, resembling labia. Undescended testicles commonly accompany ambiguous genitalia.

Ambiguous genitalia is usually not life threatening (see Causes section for exceptions), but can create social upheaval for the child and the family. For this reason, a team of experienced specialists, including neonatologists, geneticists, endocrinologists, and psychiatrists or social workers will be involved.

• Pseudohermaphroditism -- the genitalia are of one sex, but some physical characteristics of the other sex are present.
• True hermaphrodism -- very rare -- both ovarian and testicular tissue is present and the child may have parts of both male and female genitalia.
• Mixed gonadal dysgenesis -- some cells in the body have only a single X chromosome (female) and some cells in the body have XY chromosomes (male). This syndrome is variable, and depends on which cells are female, which cells are male, and what percent of each there are.
• Congenital adrenal hyperplasia -- has several forms, but the most common form causes the genetic female to appear male. Male infants with the most common form appear normal at birth, but may show premature sexual development as early as 6 months of age. Many states test for this as part of the newborn screen (the blood test your baby has at 24-48 hours of life) because CAH can be life-threatening.
• chromosomal abnormalities, including:
  • Klinefelter's syndrome (XXY) -- male, usually has small testes; causes infertility; may be associated with learning defects or mental retardation; affects 1/500-1/1000 live male births)
  • Turner's syndrome (XO) -- female; usually does not cause ambiguous genitalia (usually looks female at birth), but may have webbed neck, swelling of the hands and feet and other characteristic physical findings at birth; may not be diagnosed until later in life when sexual maturation does not take place; infertile)
• Maternal ingestion of certain medications (particularly androgenic steroids) -- may make a genetic female look more male
• Lack of production of specific hormones, causing the embryo to develop with a female body type regardless of genetic sex
• Lack of testosterone cellular receptors (so even if the body makes the hormones needed to develop into a physical male, the body is unable to respond to those hormones, and therefore, a female body-type is the result even if the genetic sex is male)

• You are concerned about the appearance of your child's external genitalia.
• Your baby takes more than 2 weeks to regain his/her birthweight, is vomiting, looks dehydrated (dry inside of mouth, no tears when crying, less than 4 wet diapers per 24 hours, eyes look sunken in), has decreased appetite, has blue spells, or has trouble breathing (these can all be signs of congenital adrenal hyperplasia).

Ambiguous genitalia may be discovered during the first well-baby examination.

• family history questions to help identify inherited chromosomal disorders
  • Is there any family history of miscarriage?
  • Is there any family history of stillbirth?
  • Is there any family history of early death?
  • Have any family members had infants who died in the first few weeks of life or who had ambiguous genitalia?
  • Is there any family history of any of the disorders that cause ambiguous genitalia (see the Common Causes section)?
• medications
  • What medications has the mother taken before or during pregnancy (especially steroids)?
• other
  • What other symptoms or abnormalities are also present?

DIAGNOSTIC TESTS

Genetic testing can determine if the child is a genetic male or female. Often a small sample of cells can be scraped from inside the cheeks (this is called a buccal smear); examination of these cells is often sufficient to determine the genetic sex of the infant. Chromosomal analysis is a more extensive cell study that may be needed in more questionable cases.

Endoscopy, abdominal X-ray, or similar tests may be needed to determine the presence or absence of internal genital structures (such as undescended testes).

Laboratory tests may help determine the functioning of reproductive structures, including tests for 17-ketosteroids.

In some cases, laparoscopy, exploratory laparotomy, or biopsy of the gonads may be necessary to confirm disorders associated with ambiguous genitalia.

TREATMENT

Depending on the cause, surgery, hormone replacement, or other treatments are used to treat conditions associated with ambiguous genitalia.

Sometimes, the ambiguity is such that a choice must be made whether to raise the child as male or female (regardless of the child's chromosomes). This choice can have tremendous social and psychological impact on the child, so counseling is usually recommended.

Note: It is often technically easier to treat (and therefore raise) the child as female (it is easier for a surgeon to make female genitalia than it is to make male genitalia), so in some cases this is recommended even if the child is genetically male. However, this is a difficult decision and should be discussed with your family, your doctor, and the surgeon involved.