Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Intersexuality is the state of a living thing of a gonochoristic species whose sex chromosomes, genitalia and/or secondary sex characteristics are determined to be neither exclusively male nor female. An organism with intersex may have biological characteristics of both the male and female sexes. 
Intersexuality is the word that medicine started to use around the fifties applied to human beings who can not be classified neither male nor female.
Intersexuality is also the word adopted by the identitary-political movement, surged at nineties, to criticize medical protocols in sex assignment and to claim the right to be heard in the construction of a new ones.
Research in the late twentieth century has led to a growing medical consensus that diverse intersex physicalities are normal, but relatively rare, forms of human biology. Perhaps the most prominent researcher, Milton Diamond, stresses the importance of care in selection of language related to intersexuality.
|“||Foremost, we advocate use of the terms "typical," "usual," or "most frequent" where it is more common to use the term "normal." When possible avoid expressions like maldeveloped or undeveloped, errors of development, defective genitals, abnormal, or mistakes of nature. Emphasize that all of these conditions are biologically understandable while they are statistically uncommon.||”|
The terms hermaphrodite and pseudohermaphrodite, introduced in the 19th century, are now considered problematic as hermaphrodism refers to people who are both completely male and completely female, something not possible. The phrase '"ambiguous genitalia'" refers specifically to genital appearance, but not all intersex conditions result in atypical genital appearance.
Disorders of sex development
The Intersex Society of North America and intersex activists have moved to eliminate the term "intersex" in medical usage, replacing it with "disorders of sex development" (DSD) in order to avoid conflating anatomy with identity. Members of The Lawson Wilkins Pediatric Endocrine Society and the European Society for Paediatric Endocrinology accepted the term "disorders of sex development" (DSD) in their "Consensus statement on management of intersex disorders" published in the Archives of Disease in Children and in Pediatrics. The term is defined by congenital conditions in which development of chromosomal, gonadal, or anatomical sex is atypical. However, this has been met with criticism from other activists who question a disease/disability model and advocate no legal definition of sexes, no gender assignments, no legal sex on birth certificates, and no official sexual orientation categories.
Alternatives to labeling these as "disorders" have also been suggested, including "variations of sex development" 
Disorders and scope
Sax's strict definition of intersex is most relevant to family practice and psychological research. Other interest groups serve different communities and concerns and so broaden the definition of intersex in these fields.
For instance, the Intersex Society of North America (ISNA) definition states that the following conditions "sometimes involve intersex anatomy":
- 5-alpha reductase deficiency
- androgen insensitivity syndrome
- congenital adrenal hyperplasia
- gonadal dysgenesis (partial & complete)
- Klinefelter syndrome
- mosaicism involving sex chromosomes
- MRKH (mullerian agenesis; vaginal agenesis; congenital absence of vagina)
- ovo-testes (formerly called "true hermaphroditism")
- partial androgen insensitivity syndrome
- progestin induced virilization
- Swyer syndrome
- Turner syndrome
Some people with some of these conditions (such as Kallmann syndrome and Turner syndrome) do not self-identify as intersex. See also 17-beta-hydroxysteroid dehydrogenase deficiency.
The prevalence of intersex depends on which definition is used.
According to the ISNA definition above, 1 percent of live births exhibit some degree of sexual ambiguity, approximately one in every hundred births.  Between 0.1% and 0.2% of live births are ambiguous enough to become the subject of specialist medical attention, including surgery to disguise their sexual ambiguity.
According to Fausto-Sterling's definition of intersex, on the other hand, 1.7 percent of human births are intersex. She writes,
|“||While male and female stand on the extreme ends of a biological continuum, there are many bodies [...] that evidently mix together anatomical components conventionally attributed to both males and females. The implications of my argument for a sexual continuum are profound. If nature really offers us more than two sexes, then it follows that our current notions of masculinity and femininity are cultural conceits.
[...] Modern surgical techniques help maintain the two-sex system. Today children who are born "either/or-neither/both" — a fairly common phenomenon — usually disappear from view because doctors "correct" them right away with surgery.
According to Leonard Sax the prevalence of intersex is seen to be about 0.018%.
Ambiguous genitalia appear as a large clitoris or small penis and may or may not require surgery.
Because there is variation in all of the processes of the development of the sex organs, a child can be born with a sexual anatomy that is typically female, or feminine in appearance with a larger than average clitoris (clitoral hypertrophy); or typically male, masculine in appearance with a smaller than average penis that is open along the underside. The appearance may be quite ambiguous, describable as female genitals with a very large clitoris and partially fused labia, or as male genitals with a very small penis, completely open along the midline ("hypospadic"), and empty scrotum.
Fertility is variable. According to some, the distinctions "male pseudohermaphrodite", "female pseudohermaphrodite" and especially "true hermaphrodite" are vestiges of 19th century thinking. According to others, the terms "male pseudohermaphrodite", and "female pseudohermaphrodite" are used to define the gender in terms of the histology (microscopic appearance) of the gonads.
With some conditions of intersex, even the chromosomal sex may not be clear. A "true hermaphrodite" is defined as someone with both male gonadal tissue (testes) and female gonadal tissue (ovarian tissue).
In 2004, researchers at UCLA published their studies of a lateral gynandromorphic hermaphroditic bird, which had a testicle on the right and an ovary on the left. Its entire body was split down the middle between male and female, with hormones from both gonads running through the blood.
This extreme example of hermaphroditism is quite rare.
Although there are no definite reports on any true hermaphroditism in humans, there is, on the other hand, a spectrum of forms of ovotestes. The varieties range, including having two ovotestes or having one ovary and one ovotestis. This is often in the form of streak gonads. Phenotype is not determinable from the ovotestes; in some case the appearance is "fairly typically female," in others it is "fairly typically male," and it may also be "fairly in-between in terms of genital development."
Intersex activist Cheryl Chase is an example of someone with ovotestes.
Other diagnostic signs
In order to help in classification, other methods than a genitalia inspection can be performed:
For instance, a karyotype display of a tissue sample may determine which of the causes of intersex is prevalent in the case.
Management of intersex can be categorized into one of the following two :
- Treatments: Restore functionality (or potential functionality)
- Enhancements: Give the ability to identify with “mainstream” people e.g. breast enlargement surgery
However, there are other categorisation systems of management of intersexed, which falls into neither category.
In any case, the most common procedure is surgery.
The exact procedure of the surgery depends on what is the cause of a less common body phenotype in the first place.
There is often concern whether surgery should be performed at all.
A traditional approach to the management of Intersexuality has been socially motivated surgery. However, some  (Alice Dreger) say that surgical treatment is socially motivated and hence ethically questionable; without evidence doctors regularly assume that intersexed persons can not have a clear identity. This is often taken further with parents of intersexed babies advised that without surgery their child will be stigmatized. Further, since almost all such surgeries are undertaken to fashion female genitalia for the child, intersex advocates point out that half the time the doctors will have performed the wrong surgery (since half of these children will have male gender identity).
In 20% to 30% of surgical cases to “treat” intersexed babies the result is loss of sexual sensation (See Newman 1991, 1992).
Most modern intersexed advocates argue surgery on intersexed babies should wait until the child can make an informed decision. Anne Fausto-Sterling's pioneering and accessible academic book, Sexing the Body, shows the abuse done to intersex bodies, arguing that operations without the consent of the child are tantamount to genital mutilation.
"Mainstream" sex development
The common pathway of sexual differentiation, where a productive human female has an XX chromosome pair, and a productive male has an XY pair, is relevant to the development of intersexed conditions.
During fertilization, the sperm adds either an X (female) or Y (male) chromosome to the X in the ovum. This determines the genetic sex of the embryo. During the first weeks of development, genetic male and female fetuses are "anatomically indistinguishable," with primitive gonads beginning to develop during approximately the sixth week of gestation. The gonads, in a "bipotential state," may develop into either testes (the male gonads) or ovaries (the female gonads) depending on the consequent events. Through the seventh week, male and female fetuses appear identical.
At around eight weeks of gestation, the gonads of an XY embryo differentiate into functional testes, secreting testosterone. Ovarian differentiation, for XX embryos, does not occur until approximately Week 12 of gestation. In normal female differentiation the müllerian duct system develops into the uterus, Fallopian tubes, and inner third of the vagina. In males the müllerian duct-inhibiting hormone MIH causes this duct system to regress. Next, androgens cause the development of the Wolffian duct system, which develops into the vas deferens, seminal vesicles, and ejaculatory ducts. By birth, the typical fetus has been completely "sexed" male or female, the hormones and genital development remaining consistent with the genetic sex.
The final body appearance doesn't always correspond with what is dictated by the genes. In other words, there is sometimes an incongruence between genotypic (chromosomal) and phenotypic sex. Although there neither no less common chromosomal sex nor mosaicism/chimerism, but just the most common types (XY or XX), less common phenotypes still appear in such cases. In this sense, the common habit in the 21st century of elevating the role of the sex chromosomes above all other factors when determining gender may be analogous to the older habit of finding "true" sex in the gonads.
This phenomenon complicates the common XY sex-determination system, because it proves that genes don't always definitely determine the sex.
|XX||Congenital adrenal hyperplasia||The most common cause of sexual ambiguity is congenital adrenal hyperplasia (CAH), an endocrine disorder in which the adrenal glands produce abnormally high levels of virilizing hormones. In genetic females, this leads to an appearance that may be slightly masculinized (large clitoris) to quite masculine.|
|XX||Progestin-induced virilisation||In this case, the male hormones are caused by use of progestin, a drug that was used in the 1950s and 1960s in order to prevent miscarriage. These individuals normally have internal and external female anatomy, with functional ovaries and will therefore have menstruation. They develop, however, some male secondary characteristics and they frequently have unusually large clitorises. In very advanced cases, such children have initially been identified as boys .|
|XX||Freemartinism||In this condition (not found in humans), a cow brings two fraternal twins, one male and one female, to term. Because (unlike humans) such twins share hormones via their placental blood interface with the mother cow, male hormones produced in the body of the fetal bull find their way into the body of the fetal cow and masculinize her brain. The result is a freemartin (unconventional heifer), a cow that will eventually try to mount other cows the way that a bull would.|
|XY||Androgen insensitivity syndrome||People with AIS have typically male chromosomes (XY), along with typically female appearance and genitalia.
Although people with AIS have a vagina, they lack a uterus, cervix of the uterus, and ovaries, and are thereby infertile. The vagina may be shorter than average; in some cases it is nearly absent. Instead of female internal reproductive organs, a person with AIS has undescended or partially descended testes, of which the person may not even be aware.
AIS may be called the genetic male's equivalent of CAH, since AIS affects people with XY genotype, while CAH affects people with XX genotype.
In complete androgen insensitivity syndrome ("CAIS"), the body reads no "male" hormones. In partial androgen insensitivity syndrome (PAIS), however, the body reads some androgens, so virilization occurs to a certain degree. PAIS results in genitalia that may be ambiguous, due to some, although limited, metabolization of the hormones produced by the testes. Ambiguous genitalia most frequently appear as a large clitoris, known as clitoromegaly, or a small penis, which is called as micropenis or microphallus.
|XY||5-alpha-reductase deficiency||In this condition, individuals have testes, as well as vagina and labia, but with a small penis capable of ejaculation instead of a clitoris (this penis, however, appears to be a clitoris at birth). These individuals are normally raised as girls. However, come puberty, their testes will descend, their voice will deepen and they often will develop a male sexual identity. People with this deficiency develop only limited facial hair.|
|XY||Persistent müllerian duct syndrome||The child has XY chromosomes typical of a male. The child has a male body and an internal uterus and fallopian tubes because his body did not produce Müllerian inhibiting factor during fetal development.|
|XY||Kallmann syndrome||This is a specific type of hypogonadotropic hypogonadism (HH) in which the distinguishing symptom is anosmia or hyposmia in addition to the HH symptoms of low levels of pituitary hormones LH and FSH. Kallmann Syndrome is not an intersex condition but does cause pubertal delay in both males and females. Some individuals with Kallmann's may regard themselves as intersex. However, this is possibly because they have other conditions such as PAIS in addition to Kallmann's. Such synchronous conditions is only present in a minority of people with Kallmann's, who mostly have no genital abnormality at birth. Therefore, mostly, there is no inconsistency of sex chromosomes with phenotype and they are therefore not intersex. Having pubertal delay but otherwise usual male or female body and fertility is not intersex.|
|Other||Less usual chromosomal sex||In addition to the most common XX and XY chromosomal sexes, there are quite a few other possible combinations such as Turner syndrome (XO), Triple X syndrome (XXX), Klinefelter syndrome (XXY), XYY syndrome (XYY), XX male, Swyer syndrome (XY female), and there are many other individuals who do not follow the typical patterns (such as individuals with four or even more sex chromosomes).|
|Other||Mosaicism and chimerism||A mix can occur, where some of the cells of the body have the common XX or XY, while some have one of the less usual chromosomal contents above. Such a mixture is caused by either mosaicism or chimerism. In mosaicism, the mixture is caused by a mutation in one of the cells of the embryo after fertilization, while chimerism is a fusion of two embryos.
Alternatively, it is simply is a mixture between XX and XY, and doesn't have to involve any less common genotypes in individual cells. This, too, can occur both as a chimerism, or that one sex chromosome has mutated into the other.
On the other hand, however, not all cases of mosaicism and chimerism involve intersex.
Intersex people are in the risk of developing gender identity disorder, feeling significant discomfort or being unable to deal with the condition.
Furthermore, in the cases where nonfunctional testes are present, there is a risk that these develop cancer. Therefore, doctors either remove them by orchidectomy or monitor them carefully. This is the case for instance in androgen insensitivity syndrome.
It should be noted however that there is a growing political intersex movement which argues against labelling these categories as disorders.
- ↑ http://www.plantpath.cornell.edu/glossary/Defs_I.htm On-Line Glossary of Technical Terms in Plant Pathology
- ↑ Intersex Society of North America | A world free of shame, secrecy, and unwanted genital surgery
Diamond, Milton (1997). "Management of intersexuality: Guidelines for dealing with individuals with ambiguous genitalia". Archives of Pediatrics and Adolescent Medicine. June. Retrieved 2007-04-08. Unknown parameter
- ↑ Intersex Society of North America (May 24, 2006). Is a person who is intersex a hermaphrodite? Retrieved 25 November, 2006.
- ↑ Intersex Society of North America (May 24, 2006). Is intersex the same as "Ambiguous genitalia"? Retrieved 25 November, 2006.
- ↑ Intersex Society of North America (May 24, 2006). Why is ISNA using "DSD"? Retrieved June 4, 2006.
- ↑ http://www.lwpes.org/ LWPES
- ↑ http://www.eurospe.org/ ESPE
- ↑ Hughes IA, Houk C, Ahmed SF, Lee PA; LWPES Consensus Group; ESPE Consensus Group. Consensus statement on management of intersex disorders. Arch Dis Child. 2006 July;91(7):554-63. Epub 2006 April 19.
- ↑ Lee, P. A., C. P. Houk, S. F. Ahmed, and I. A. Hughes. 2006. Consensus statement on management of intersex disorders. Pediatrics 118 (2):e488-500. http://pediatrics.aappublications.org/cgi/reprint/118/2/e488
- ↑ French-speaking Intersex Network of Europe (July 12, 2005). Frequently Asked Questions. Translated from French-speaking by OII. Retrieved June 4, 2006.
- ↑ Diamond M, Beh HG (27 July 2006). Variations of Sex Development Instead of Disorders of Sex Development. Arch Dis Child
- ↑ "Intersex conditions". Retrieved 2007-12-08. Text " Intersex Society of North America " ignored (help)
- ↑ How common is intersex? | Intersex Society of North America
- ↑ 15.0 15.1 15.2 Fausto-Sterling, Anne (2000). Sexing the Body: Gender Politics and the Construction of Sexuality. New York: Basic Books.
- ↑ Sax, Leonard (2002). "How common is intersex? a response to Anne Fausto-Sterling". Journal of Sex Research. 39 (3): 174–178. Retrieved 2007-04-08.
- ↑ Langman, Jan; Thomas Sadler (2006). Langman's medical embryology. Hagerstwon, MD: Lippincott Williams & Wilkins. p. 252. ISBN 0-7817-9485-4.
- ↑ Sax, Leonard (2005). Why Gender Matters: What Parents and Teachers Need to Know About the Emerging Science of Sex Differences. New York: Doubleday.
- ↑ "ovo-testes (formerly called "true hermaphroditism")". Retrieved 2007-12-09. Text " Intersex Society of North America " ignored (help)
- ↑ Weil, Elizabeth (September, 2006). What if It's (Sort of) a Boy and (Sort of) a Girl? The New York Times Magazine
- ↑ Enhancing Human Traits: Ethical and Social Implications Edited by Erik Parens, Washington DC, Georgetown University Press, 1998
- ↑ 22.0 22.1 Holmes M. (2002). Rethinking the Meaning and Management of Intersexuality. Sexualities , 159-180."
- ↑ 23.0 23.1 23.2 Kolodny, Robert C.; Masters, William H.; Johnson, Virginia E. (1979), Textbook of Sexual Medicine (1st ed.), Boston: Little, Brown and Company
- ↑ Intersex Society of North America (May 24, 2006). Does having a Y chromosome make someone a man? Retrieved 25 November, 2006.
- ↑ 2000 Intersex Society of North America - What is Progestin Induced Virilisation?
- ↑ De Marchi M, Carbonara AO, Carozzi F; et al. (1976). "True hermaphroditism with XX/XY sex chromosome mosaicism: report of a case". Clin. Genet. 10 (5): 265–72. PMID 991437.
- Beh, Hazel Glenn, Milton Diamond. 2000. An Emerging Ethical and Medical Dilemma: Should Physicians Perform Sex Assignment on Infants with Ambiguous Genitalia?. Michigan Journal of Gender & Law, Volume 7 (1): 1-63, 2000.
- Human Rights Investigation into the medical "normalization" of intersex people - a report of a hearing of the San Francisco Human Rights Commission - PDF format
- Blackless M, Charuvastra A, Derryck A, Fausto-Sterling A, Lauzanne K, Lee E (2000). "How sexually dimorphic are we? Review and synthesis". Am J Hum Biol. 12 (2): 151–166. doi:10.1002/(SICI)1520-6300(200003/04)12:2<151::AID-AJHB1>3.0.CO;2-F. PMID 11534012.
- Dreger AD, Chase C, Sousa A, Gruppuso PA, Frader J (2005). "Changing the nomenclature/taxonomy for intersex: a scientific and clinical rationale". J. Pediatr. Endocrinol. Metab. 18 (8): 729–33. PMID 16200837.
- "A CONVERSATION WITH -- Anne Fausto-Sterling; Exploring What Makes Us Male or Female - New York Times (January 2, 2001)". Retrieved 2007-12-09.
- Sax, Leonard. How common is intersex? A response to Anne Fausto-Sterling. J Sex Research 39:174-9, 2002
- (2004) The Evolution of Self-Fertile Hermaphroditism: The Fog Is Clearing. PLoS Biol 3(1): e30.
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