Ambiguous genitalia is a birth defect where the outer genitals do not have the typical appearance of either a boy or a girl.
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. The father "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 come 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. The genitalia makes it difficult to easily identify 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. For example, a genetic male may have developed the appearance of a normal female.
Typically, ambiguous genitalia in genetic females (babies with two X chromosomes) has the following features:
In a genetic male (one X and one Y chromosome), ambiguous genitalia usually include the following features:
Ambiguous genitalia is usually not life threatening (see Causes section for exceptions), but it can create social problems for the child and family. For this reason, a team of experienced specialists, including neonatologists, geneticists, endocrinologists, and psychiatrists or social workers will be involved in the child's care.
Because of the potential social and psychological effects of this condition, parents should make a decision about whether to raise the child as a male or female early after diagnosis, preferably within the first few days of life. This is an important decision, so parents should not rush it.
You are concerned about the appearance of your child's external genitalia, or your baby:
These can all be signs of congenital adrenal hyperplasia.
Ambiguous genitalia may be discovered during the first well-baby examination.
The doctor will perform a physical examination, which may reveal genitals that are not "typical male" or "typical female," but somewhere in between.
The doctor will ask medical history questions to help identify any chromosomal disorders. Questions may include:
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 child's cheeks (this is called a buccal smear). Examining these cells is often enough to determine the genetic sex of the infant. Chromosomal analysis is a more extensive cell study that may be needed in more questionable cases.
Laboratory tests may help determine how well the reproductive organs are functioning. This can include tests for adrenal and gonadal steroids.
Depending on the cause, surgery, hormone replacement, or other treatments are used to treat conditions that can cause ambiguous genitalia.
Sometimes, the parents must choose whether to raise the child as male or female (regardless of the child's chromosomes). This choice can have a big 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. You should discuss it with your family, your child's doctor, the surgeon, your child's endocrinologist, and other health care team members.
Genitals - ambiguous
Diamond AD, Yu RN. Sexual differentiation: Normal and abnormal. In: Wein AJ, ed. Campbell-Walsh Urology. 10th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 133.
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.
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