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Intersex refers to any biological ambiguity of sex. There are many distinct conditions which can lead to this. In some cases this involves ambiguous genitalia (full or partial hermaphroditism); in other cases there is a lack of observable external differences at birth, but abnormalities exist at the hormonal or genetic levels.

Intersex can be distinguished from transsexualism, in that intersex individuals have natural physical sex ambiguity; whereas any ambiguity in a transsexual's body is artifical. Like transsexual individuals, intersex individuals sometimes come to feel they were assigned the wrong gender at birth, and seek to change that assignment; this is generally distinguished from transsexualism, though it tends to be used to support the supposition that each person has an intrinsic gender identity that cannot be wrongfully imposed.

Using Anne Fausto-Sterling's definition, 1.7% of all human births are intersex.[1]

An important point to understand regarding the biology of sex determination - all embryos start off undifferentiated. The female clitoris and male nipples reflect this early undifferentiated state. They have both the Wolffian and Mullerian ducts, which ultimately give rise to the two sexes. Male=Wolffian Female=Mullerian. For the Wolffian pattern to produce a non-intersex male, there must be testosterone and suppression of the Mullerian duct[2] This might make the female pattern sound like the default, but the development of functional ovaries requires activity from at least two X chromosomes.[3]


[edit] Some examples

  • XY females or Swyer Syndrome: the SRY gene, present on the Y chromosome, causes the development of testis rather than ovaries, and starts the sex differentiation process. If this gene is damaged or deleted, then a female course of development will proceed to an extent, rather than a male course. The individual will have mainly female anatomy, but will have streak gonads instead of functional ovaries or testes. The individual will not be able to produce viable sperm/eggs but with donated eggs can become pregnant.[4]
  • XX males: if the SRY gene somehow migrates from the Y chromosome to another chromosome, then a male course of development will ensue despite the XX karyotype.[5] Known cases are due to SRY migrating to the X chromosome. Sterile.
  • Complete androgen insensitivity syndrome: normal XY karyotype, but individual has damage to genes necessary for testosterone to have its effect. As a result, the individual will undergo a mostly female development of the body. External sex organs will be female, but will have male internal sex organs (including testes instead of ovaries). High testosterone levels, above the male norm, but the body will fail to respond to testosterone in the usual male manner. Due to high testosterone levels, the body will convert some of the testosterone into estrogen, which can then cause normal female puberty, except menstruation will not occur. The typical phenotype for this syndrome is women who are extremely tall, not particularly curvy, and lacking in body hair (yes, the Western beauty ideal is very similar to the appearance of a woman who has an intersexuality syndrome).
  • Partial androgen insensitivity syndrome: some deficiency in genes responsible for response to testosterone, but not total. This represents a range of conditions, at one extreme the individuals are mostly similar to normal males, but have some slight feminine characteristics and fertility issues; as the level of insensitivity increases, the result is less and less masculine, and more and more feminine. Many people with partial androgen insensitivity undergo sex reassignment therapy to make their gender more definitive.
  • 5α-reductase deficiency: An error in the enzyme that changes testosterone to dihydrogen testosterone (DHT) results in low levels of DHT, which is a more active hormone than mere testosterone.[6]
  • Congenital adrenal hyperplasia(CAH): Due to abnormal function of the adrenal glands, cortisol and aldosterone are produced insufficiently while androgens are overproduced. Classic CAH requires medical intervention as these hormone imbalances can be life-threatening for infants due to resulting electrolyte imbalances and hypertension.[7] Additionally, in females, it can cause a male external sex, or with later onset cause masculine-like puberty.
  • Genetic chimerism/mosaicism: In chimerism, two zygotes, one XX and one XY, fuse together before cell differentiation, embryogenesis, and implantation happen. As a result, some parts of the body have the XX genome, while other parts have the XY genome. In both cases, the phenotypical consequences (including gonadal and genital) vary widely, depending on the exact distribution of the two (or more) karyotypes throughout the body.

[edit] In Jewish Texts

In Jewish texts, the androgynos is a "hermaphrodite", or someone displaying both male and female characteristics. The androgynos is one of the four non-binary genders in the Talmud, Mishnah and other rabbinic texts.[8][9][10] There is also the tumtum, a person whose sexual characteristics are intermediate or obscured. There is also the ay'lonit, which is an afab person who develops male characteristics at puberty is infertile. There is also the saris, which is a person who is amab but develops female characteristics as puberty and/or is lacking a penis. A saris can be “naturally” a saris (saris hamah), or become one through human intervention (saris adam).[11]

[edit] Politics vs. reality

Right-wing, conservative and radical feminist views on various issues (e.g. gender relations, transgenderism, etc.) assume that male and female are clearly distinct. The existence of intersex people undermines that assumption of gender essentialism. There is no one single feature that makes a person female or male (despite the overly simplistic assumption of many that sex can be defined in terms of what types of chromosomes one has). In biological terms, female and male exist on a continuum, even though the vast majority of individuals exist clearly at one end or the other, and only a small minority occupy intermediate positions. The question of sex/gender is not always decidable: at the extremes of the continuum the correct answer is clear, yet there are places in the middle where the question is essentially undecidable and arbitrary.

[edit] Footnotes

  1. Fausto-Sterling, Anne (2000). Gender Politics and the Construction of Sexuality. New York: Basic Books. ISBN 0-465-07713-7. 
  2. Sexual Differentiation
  3. Learning Objectives
  4. Genetics Home Reference Swyer Syndrome
  5. Genetics Home Reference 46,XX testicular disorder of sex development
  6. 5-Alpha-Reductase Deficiency Background, Pathophysiology, Epidemiology
  7. Congenital adrenal hyperplasia
  8. "Terms for Gender Diversity in Classical Jewish Texts". Retrieved 2012-10-28. 
  9. "Gender Diversity in Halacha (The Way We Walk)". Retrieved 2012-10-28. 
  11. "Terms for Gender Diversity in Classical Jewish Texts". Retrieved 2012-10-28. 
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