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Disorders of sex development; DSDs; Pseudohermaphroditism; Hermaphroditism; Hermaphrodite
Intersex is a group of conditions where there is a discrepancy between the external genitals and the internal genitals (the testes and ovaries).
The older term for this condition, hermaphroditism, came from joining the names of a Greek god and goddess, Hermes and Aphrodite. Hermes was a god of male sexuality (among other things) and Aphrodite a goddess of female sexuality, love, and beauty.
Although the older terms are still included in this article for reference, they have been replaced by most experts (and patients and families) because they are misleading, confusing, and insensitive. Increasingly this group of conditions is being called disorders of sex development (DSDs).
Intersex can be divided into four categories:
Each one is discussed in more detail below. Note: In many kids the cause of intersex may remain undetermined, even with modern diagnostic techniques.
46, XX Intersex. The person has the chromosomes of a woman, the ovaries of a woman, but external (outside) genitals that appear male. This usually is the result of a female fetus having been exposed to excess male hormones before birth. The labia ("lips" or folds of skin of the external female genitals) fuse, and the clitoris enlarges to appear like a penis. Usually this person has a normal uterus and Fallopian tubes. This condition is also called 46, XX with virilization. It used to be called female pseudohermaphroditism. There are several possible causes:
46, XY Intersex. The person has the chromosomes of a man, but the external genitals are incompletely formed, ambiguous, or clearly female. Internally, testes may be normal, malformed, or absent. This condition is also called 46, XY with undervirilization. It used to be called male pseudohermaphroditism. Forming normal male external genitals depends on the appropriate balance between male and female hormones; therefore, it requires the adequate production and function of male hormones. 46, XY intersex has many possible causes:
True Gonadal Intersex. Here the person must have both ovarian and testicular tissue. This might be in the same gonad (an ovotestis), or the person might have one ovary and one testis. The person may have XX chromosomes, XY chromosomes, or both. The external genitals may be ambiguous or may appear to be female or male. This condition used to be called true hermaphroditism. In most people with true gonadal intersex, the underlying cause is unknown, although in some animal studies it has been linked to exposure to common agricultural pesticides.
Complex or Undetermined Intersex Disorders of Sexual Development. Many chromosome configurations other than simple 46, XX or 46, XY can result in disorders of sex development. These include 45, XO (only one X chromosome), and 47, XXY, 47, XXX -- both cases have an extra sex chromosome, either an X or a Y. These disorders do not result in an intersex condition where there is discrepancy between internal and external genitalia. However, there may be problems with sex hormone levels, overall sexual development, and altered numbers of sex chromosomes.
Allen L. Disorders of sexual development. Obstet Gynecol Clin North Am. 2009;36:25-45.
Donohoue PA. Disorders of sex development (intersex). In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 582.
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