PM5351: Intersex

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, chromosomal or genetic levels.

Intersex can be distinguished from transsexuality, in that intersex individuals have clear biological signs of sex ambiguity; transsexual individuals show no such signs, but feel they were born with the "wrong" gender. It has been claimed that many transsexual individuals have some unknown biological sex ambiguity, however there is as yet insufficient evidence to prove or disprove that claim. 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 on the grounds that there are known biological reasons to suppose that assignment at birth could have been mistaken. Generally transgender refers to people who feel they have the wrong gender, but there is no known biological ambiguity (as there is in the case of intersex). There are two possibilities here. One is that, there actually is some biological ambiguity present, but it is not something medical science is currently aware of. (We still don't 100% understand the biology of sex determination.) The other possibility is that, there is no biological ambiguity, and the transgender feelings have a non-biological origin, as a result of some form of psychosocial process. To be honest, we don't really know which is the case here, since on the one hand we lack a full understanding of the biology, on the other hand we lack a full undertanding of the psychology too. Different people will take different viewpoints, and that includes transgender people - some believe their transgenderism is biological in origin (even if there is no clear evidence of a biological basis in their particular case); some others will prefer to see it as having some kind of psychological origin.

An important point to understand regarding the biology of sex determination - female is the body's default, male is a deviation from that default. As we will see, damage or deletion of a single gene is sufficient to change male DNA into female.

Some examples:

  • XY females: 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 instead, rather than a male course. The individual will be sterile.
  • 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 karotype. Known cases are due to SRY migrating to the X chromosome. Sterile.
  • Total androgen insensitivity syndrome: normal XY karotype, 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.
  • 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
  • Genetic mosaics: two embryos, one XX and one XY, fuse together. As a result, some parts of the body have XX karotype and others XY. The phenotypical consequences (including gonadal and genital) vary widely, depending on the exact distribution of the two karotypes throughout the body.
Right-wing/conservative 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 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; there are places in the middle where the question is essentially undecidable and arbitrary