Ambiguous genitalia
Alternative names:
genitals - ambiguous
Definition:
A congenital physical abnormality where the outer genitals do not have the typical appearance of either sex. (See also genetics)
Considerations:
The genetic sex of a child is determined at conception. The egg cell (ovum) contains a chromosome called the X chromosome. Sperm cells contain either an X chromosome or one called the Y chromosome. These determine the child's genetic sex. Normally an infant will inherit ONE PAIR of these "sex chromosomes" (two chromosomes). Thus, it is the father who "determines" the genetic sex of the child. An infant who inherits the X chromosome from the father is a genetic female (XX pattern) and one who inherits the Y chromosome is a genetic male (XY pattern).
The reproductive organs and genitals associated with "female" or "male" arise from the same initial (fetal) tissue. 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 (by physical examination) as male or female. The extent of the ambiguity varies, and the infant can look very much like a "normal" infant of the opposite sex. In very rare instances, the physical appearance may be fully developed as the opposite of the genetic sex (for example, a genetic male may have normal female appearance or a genetic female may have a near-normal male appearance).
Typical ambiguous genitalia in genetic females include an enlarged clitoris that has the appearance of a small penis. The urethral opening can be anywhere along, above, or below the surface of the clitoris, which may be considered normal or a common abnormality of anatomic urethra placement (such as hypospadias). The labia may be fused together, 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, findings of ambiguous genitalia include a small penis, less than 2 to 3 centimeters (0.8 to 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 perineum, further making the infant appear to be a female. There may be a small scrotum with any degree of separation, resembling labia. Undescended testicles commonly accompany ambiguous genitalia.
Uncertain or mistaken sex is usually not a physical threat to life (although in some conditions it can be), but can create social upheaval for the child and the family.
Common causes:
- pseudohermaphroditism
- true hermaphrodism (very rare)
- testicular feminization syndrome
- mixed adrenal dysgenesis
- congenital adrenal hyperplasia (usually genetic female appears male)
- chromosomal abnormalities including
- maternal ingestion of certain medications such as androgenic steroids, trimethadione
- 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
Note: There may be other causes of ambiguous genitalia. This list is not all inclusive, and the causes are not presented in order of likelihood. The causes of this symptom can include unlikely diseases and medications. Furthermore, the causes may vary based on the specific characteristics of the symptom such as location, quality, and associated complaints. Use the Symptom Analysis option to explore the possible explanations for ambiguous genitalia, occurring alone or in combination with other problems.
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