The popular term "Intersex" or more technical "Disorders/Differences of Sex Development" (DSD for short) refers to being born with features of anatomy, physiology and/or hormones that do not fit the typical definition of biological male or female. Intersex IS NOT the same as transgender, although there is some overlap between the two.
The oldest term used was "Hermaphrodite" from Greek mythology, but now it is reserved to refer to animal species having both sets of functional reproductive systems such as earthworms and sometimes used for humans having both ovarian and testicular tissue. The popular myth of humans with both sets of functional sex anatomy able to impregnate themselves does not really exist.
Here is a basic intersex fact sheet from the U.S. National Library of Medicine: Medline Plus definition
A fact sheet with a more expansive definition issued by the United Nations: UN Definiton
An often cited study calculated that 1.7% of humans are born intersex. Others omit one or more conditions used in that study to arrive at lower figures:
Blackless, M., Charuvastra, A., Derryck, A., Fausto‐Sterling, A., Lauzanne, K., & Lee, E. (2000). How sexually dimorphic are we? Review and synthesis. American Journal of Human Biology: The Official Journal of the Human Biology Association, 12(2), 151-166.
Chapter 24 has the current medical knowledge on all known DSDs and Chapter 21 the current medical knowledge on transgender endocrinology.
Melmed, S., Auchus, R., Goldfine, A., Koenig, R., Rosen, C., & Williams, R. (2021). Williams textbook of endocrinology (Fourteenth edition.). Elsevier.
Humans with bodies that do not readily sort as male or female pose a challenge to any society that strictly labels everyone as either male or female. In some cultures the problem is traditionally solved by killing any sex-ambiguous infant at birth so everyone left really IS male or female. Starting in the 1950s our society began a somewhat less cruel approach by labeling intersex as a "psycho-social emergency", surgically altering ambiguous children to whichever sex was technically most feasible, using hormones to simulate the correct puberty, then hiding the reasons for that treatment in hopes the child would grow up as a normal-unconflicted heterosexual. In effect making the problem disappear.
This was based on theories by psychologist John Money that infants are born a "blank slate" that can be brought up as either sex as long as the genitalia and sex of rearing match and they are unaware of the process.
Money, J., & Ehrhardt, A. (1972). Man & woman, boy & girl: the differentiation and dimorphism of gender identity from conception to maturity. Johns Hopkins University Press.
His test case was David Reimer, whom he reassigned as female after a circumcision accident and for many years was considered a great success. Then in the 1990s sexologist Milton Diamond followed up on David Reimer and found he had never really adjusted to life as a girl, reverted to a male and eventually committed suicide. That shed doubt on the whole basis of the accepted intersex treatment protocol
Colapinto, J. (2000). As nature made him : the boy who was raised as a girl (1st ed.). HarperCollins.
Then a generation of these children grew up and said there WERE problems: surgery sometimes needed many revisions, scarring, numbness, and pain. The assigned sex might be wrong. The secrecy often led to distrust of doctors, worsened because doctors as a whole were never trained in treating intersex patients. The frequent examinations and even photography were traumatic. At the same time, this protocol made them invisible to the general public.
All this led to a conference in 2006 to reconsider intersex treatment and the publication of the "Consensus statement on management of intersex disorders" (often referred to as the 2006 Chicago Consensus Statement) is the medical profession's current guide to classification and treatment for Intersex/DSD. It set out a new system of nomenclature, replaced the term "intersex" with the equally problematic term "Disorders of Sex Development", called for and end to secrecy and a multidisciplinary team approach to treatment. But it did not curtail surgical correction and many doctors still follow the old protocol with all its problems to this day.
Hughes, I. A., Houk, C., Ahmed, S. F., Lee, P. A., & Society, L. W. P. E. (2006). Consensus statement on management of intersex disorders. Journal of pediatric urology, 2(3), 148-162.
This means that many college-age intersex adults were never told they were intersex or the specifics of their condition or treatment. They come to college only knowing they have an unusual body and possibly years of medical treatment and all questions have been deflected or even told they had cancer. They may feel they are the only person like themselves. This guide seeks to provide sources of accurate information, narratives by intersex people and support groups.
