Ambiguous Genitalia

Ambiguous Genitalia: Common Causes

• 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)