TranzFat

Below we provide a summary of statistics drawn from an article by Brown University researcher Anne Fausto-Sterling.² The basis for that article was an extensive review of the medical literature from 1955 to 1998 aimed at producing numeric estimates for the frequency of sex variations. Note that the frequency of some of these conditions, such as congenital adrenal hyperplasia, differs for different populations. These statistics are approximations.

Not XX and not XY one in 1,666 births

Klinefelter (XXY) one in 1,000 births

Androgen insensitivity syndrome one in 13,000 births

Partial androgen insensitivity syndrome one in 130,000 births

Classical congenital adrenal hyperplasia one in 13,000 births

Late onset adrenal hyperplasia one in 66 individuals

Vaginal agenesisone in 6,000 births

Ovotestes one in 83,000 births

Idiopathic (no discernable medical cause) one in 110,000 births

Iatrogenic (caused by medical treatment, for instance progestin administered to pregnant mother) no estimate

5 alpha reductase deficiency no estimate

Mixed gonadal dysgenesis no estimate

Complete gonadal dysgenesis one in 150,000 births

Hypospadias (urethral opening in perineum or along penile shaft) one in 2,000 births

Hypospadias (urethral opening between corona and tip of glans penis) one in 770 births

Total number of people whose bodies differ from standard male or female one in 100 births

Total number of people receiving surgery to “normalize” genital appearance one or two in 1,000 births

¹ Dreger, Alice Domurat. 1998. Ambiguous Sex—or Ambivalent Medicine? Ethical Issues in the Treatment of Intersexuality. Hastings Center Report, 28, 3: 24-35.

² Blackless, Melanie, Anthony Charuvastra, Amanda Derryck, Anne Fausto-Sterling, Karl Lauzanne, and Ellen Lee. 2000. How sexually dimorphic are we? Review and synthesis. American Journal of Human Biology 12:151-166.