Developmental Disorders of the Vagina and Vulva

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Overview, Causes, & Risk Factors

With the union of a sperm and an ovum, an embryo acquires the chromosomes that determine the sex of the fetus (XX=female; XY=male). For the first 6 weeks, the sex of the fetus is not distinguishable.

At about 6 weeks gestation, ovaries begin to develop in those with two X chromosomes, and testicles develop in those with an X and Y chromosome. Sexual ambiguity may arise when additional X chromosomes are present, or the Y chromosome is not functioning correctly.

The X chromosome is the primary determinant of feminine traits. However, geneticists have noted over 200 traits that are thought to be X-chromosome linked (such as hemophilia and color blindness). In contrast, the Y chromosome has only been linked with testicular formation and the development of male secondary sexual characteristics during puberty.

As fetal development progresses through the pregnancy, problems may arise in the development of internal and/or external sexual organs. Since embryonic tissue is initially the same, with no male and/or female differentiation, such problems may cause genetic males to have "female" genital structures and genetic females to have "male" genital structures.

An example of this is true hermaphroditism. In the past, most of these individuals were raised as males since their external genitalia appeared more masculine. In fact, had early diagnosis been available, most should have been raised as females since they all developed significant breasts and many menstruated. After surgical removal of testicular tissue, some have even become pregnant and delivered normal children.