Gender Identity Disorder Information


About the word "Hermaphrodite"
Victorian doctors believed that the gonads were the seat of "true sex," and thus created a system of nomenclature -- in the absence of any knowledge of genetics, endocrinology, or embryology -- which categorized people as "male pseudohermaphrodite," "female pseudohermaphrodite," or "true hermaphrodite." It's time to eliminate this quaint Victorianism from modern medical practice.

The word "hermaphrodite" implies that a person is born with two sets of genitals -- one male and one female -- and this is actually something that cannot occur.

The qualifiers "male" and "female," because they are based only upon the gonadal histology, frequently contradict the sex of assignment, and thus are very misleading and disturbing for parents and patients.

The qualifiers "pseudo" and "true" are even more harmful, because they imply a sort of authenticity, or lack of same, that carry powerful emotional baggage.

As with any contraversial term there are those that support using it. Some intersexed people want to reclaim the word, free of it's Victorian medical misuse.

Intersexuality (abbreviated IS) is a broad class of medical conditions that features "congenital anomalies of the reproductive and sexual system." A person with an intersex condition is born with sex chromosomes, external genitalia, or an internal reproductive system that is not considered "normal" for either a male or female.

The causes and presentations of intersex conditions vary greatly. There are environmental factors, genetic factors, and developmental factors and the effects of them on a developing child range from "nothing apparent" to "obvious at birth." Those conditions that are obvious at birth garner the most attention from the medical community, while there are people who are intersexed who may be so mildly affected they will never be clinically identified.

Most of the birth disorders that are classified as "intersex conditions" are treated as "unusual," and it is not uncommon to find them listed among "rare diseases." The general public - even many doctors - have no familiarity with intersex conditions or people. At best an individual may have heard of the now out of favor term "hermaphrodite" (taken to mean someone with both male and female genitals). Which is ironic, because people who used to be called "true hermaphrodites" are among the rarest of all intersex conditions. For the most part, though, schools usually omit any mention of intersex conditions in biology, health, or sex educations classes.

This is unfortunate because intersex conditions are actually NOT rare! Some intersex conditions are among the most common birth disorders in the world - collectively the total number of people whose bodies differ from standard male or female affects as many as 1 out of every 100 people!

So why haven't you heard of intersexuality? Good question. It is certainly a major oversight on the part of society and educators to omit mention of it.

IS and GID

Because the physical sex of intersexed people is often ambiguous, parents and doctors usually "choose" whether the child will be identified and reared as either male or female. As there is no way to know a newborn's gender identity these decisions are often made somewhat arbitrarily. If the child doesn't have a penis the bias is toward raising the child as a girl simply because "assignment surgery" to configure the child as female is simpler and more advanced than surgical techniques to construct external male genitals. Conversely, in cases where the child has a penis the bias is toward raising the child as a male (unless the doctor judges that it is "too small"). Children born with what doctors judge to be an enlarged clitoris are also sometimes assigned as males.

A recent study from Johns Hopkins University led to their recommendation that children born with a condition called "micropenis" (where the penis fails to grow for the final two-thirds of the embryo's development) be reared as males. The report claimed that 20% of those raised as girls were satisfied with their surgically constructed vaginas, while 50% of those raised as men were satisfied with their male genitals after testosterone hormone therapy. However the study found that those raised male considered themselves masculine and those raised female considered themselves feminine. Intersex activists like to point out that these studies are often biased or use very small test groups to determine medical and surgical policy where intersexed children are concerned. In this particular instance the test base consisted of just 16 people, now adults, who were diagnosed with micropenis as babies. 12 were raised as males, 4 as females. [source].

Another study on the same topic, conducted after the Johns-Hopkins one but by other researcher using Johns Hopkins former patients, found surprisingly different results (and also appeared to have much greater success in getting intersex people to respond, possibly owing to the many negative experiences with Johns Hopkins that have been reported in the Intersex Community). The results of that study found:

Sixteen participants (76%) were mainly satisfied with their male sex of rearing established by physicians and parents. Five participants (24%) reported dissatisfaction with their male sex of rearing, 1 of whom preferred to think of himself as intersex and 1 reassigned her gender to that of a woman in early adulthood. Fourteen participants (78%) were mainly satisfied with their physician/parent-established female sex of rearing. Four participants (22%) reported dissatisfaction with their female sex of rearing. Among the dissatisfied women, 1 reported that her female homosexual orientation was an obstacle and as a result she would have preferred a male sex of rearing, and 1 subject reassigned his sex to that of an intersexed man in early adulthood. Satisfaction with physician/parent-established sex of rearing did not differ between men and women. [ source ]

For more information on the subject of surgical assignments from the intersexed perspective you may wish to visit the Intersex Society of North America web site.

The result of this practice of choosing a sex shortly after birth has been that, inevitably, for some of the children the sex the doctors and/or parents chose was not in sync with the child's gender identity. If that is the case, the intersexed person is in the same position as anyone who has a physical sex that is incongruous with gender identity. In other words, they have a Gender Identity Disorder.

A person need not be intersexed to have a Gender Identity Disorder, and not everyone with GID is intersexed. For some intersexed children the assigned sex happens to be in sync with their gender identity, in which case they do not have a gender-related conflict. The same can be said of those who are not born intersexed, the only difference being that it was Nature that "assigned" their sex, not a doctor.



I mention these old medical terms, rooted in Victorian-era medicine, because they are still pervasive in the definitions used by modern medicine.

Intersex conditions traditionally have been divided into the following 5 simplified classifications based on the differentiation of the gonad:

  1. Female pseudohermaphrodite - Two ovaries
  2. Male pseudohermaphrodite - Two testes
  3. True hermaphrodite - Ovary and/or testis and/or ovotestis
  4. Mixed gonadal dysgenesis - Testis plus streak gonad
  5. Pure gonadal dysgenesis - Bilateral streak gonads
    (A streak gonad is dysgenetic and resembles ovarian stromal tissue. No germ cells are present.)

These classifications are based solely on the physical state of the gonads. They do not take into account the individual's endocrinology, genetic makeup, or embryological development. And, because many different intersex conditions can produce a child of similar appearance, these terms do little for the purpose of diagnosing cause. Furthermore, it is often left to the doctor to decide if the child with ambiguous genitalia has a small penis or an enlarged clitoris. Modern medicine obviously needs to go beyond this trivial visual examination for any meaningful diagnosis.


There are literally hundreds of specific forms of intersexuality covered under the term. Sometimes intersex conditions are subcategorized by possible cause or presentation:

Chromosomally Intersexed - probably the most common form of intersexuality involves people who are either missing a sex chromosome or have extra sex chromosomes. The effects of such a condition vary widely. Some people show no outward signs of being intersexed while in others it is apparent at birth.

Genetically Intersexed - technically would encompass "chromosomally intersexed" people too. However it usually refers to individuals who have normal chromosomal makeup (XX or XY) but have a faulty gene on one of those chromosomes resulting in an intersex condition.

Physically Intersexed - the person has physical characteristics of both male and female. Usually this refers to a person with "ambiguous genitalia" (genitals that do not appear to be "normally" male or female). However it is also sometimes used to refer to anyone with a genetic or chromosomal cause, since those are physical characteristics as well, albeit at the molecular level. This term also encompasses those who present with ambiguous genitalia caused by developmental anomolies in the womb of environmental (termed "Iatrogenic"), rather than genetic, cause.


Ovatestis - formerly referred to as "true hermaphroditism." People with Ovatestis are individuals who have both ovarian and testicular tissue. Please note that this does not mean the person has both male and female genitalia! This diagnostic nomenclature is applied regardless of the peripheral karyotype. Technically, the anachronistic term "True Hermaphrodite" is still in use to refer to those withouth gonads that are ovoteste, but have separate organs, with an ovary on one side and a testis or ovotestis on the other. Additionally, testicular and ovarian tissue may develop on the same side of the pelvis as a separate ovary and testis. These gonads are almost always contained within the abdomen at the positions of ovaries in women, but ovatestes that descend from that position are not unheard of.

People with Ovatestis usually have ambiguous genitalia at birth, but how ambiguous is highly individual. The majority of affected individuals have been reared as males. However, because of functioning normal ovarian tissue, most people with this problem experience breast development at puberty, and 40% with a 46,XX karyotype menstruate. Note that some people with this condition are chromosomally mosaic (see below) but, because karyotyping tests can be inaccurate in cases of mosaicism, they may "officially" be delcared to be XX or XY. The author of this site is personally aware of at least one individual who was tested as being of a male karyotype (XY) and appeared to have underdeveloped, but complete, male genitals. Nonetheless, medical imaging uncovered the presence of an ovary and partially developed uterus. There was also a Urological medical journal (cited elsewhere on this site) concerning an otherwise "normal male" who presented with blood in his urine. An ultrasound and MRI confirmed the presence of a partially developed vagina and uterus; as well as chromosomal anomolies.

In some of these cases of of chromosomal mosaicism and the presence in one individual of organs of both sexes (or combined organs of both sexes) I've read the cause postulated to have been the absorbtion of an opposite sex fraternal twin in the womb, but there is no way of verifying if this theory is correct.

While this birth condition accounts for less than 10% of all intersex diagnoses it is, ironically, the most widely known intersex condition among the general population.


This is a congenital abnormality in the development of male genitals whereby there is a urethral opening in the penis, sometimes extending down the shaft so that urine exits at the base of the penis instead of the tip.

  • Discovery: 2nd Century A.D. by Galen
  • Usually Diagnosed: at birth, though may appear on prenatal fetal ultrasound scans
  • Frequency: 1 in 300 births in the United States (and increasing).
  • More information:

Sex Chromosome Mosaicism

" Mosaicism," simply put, is a genetic condition in which a person has either more or less than 46 chromosomes in at least some of their cells. Most people are unaware that such a condition is even possible, let alone relatively common.

"[There are] different degrees of mosaicism. That is the percentage of cells in your body that have the extra chromosome. Even when they do a blood test and tell you that '100% of the cells are XXY,' what they are saying is '1005 of the cells from your blood that we tested have XXY.' They may have missed some cells without an X chromosome, and they do not [know] if the cells in your brain, in your skin, in your gut, etc., etc. have all XXY. The concept is that there are men with 100% XXY in all their cells and some others that have a variable percentage." - Dr. Arturo Rolla, from the KS&A XXY+ADULTS email list, Feb. 28, 1999.

It should be noted, however, that "It seems likely everyone has some small number of cells in their body which are chromosomally abnormal. However, even a very minor degree of mosaicism could be important if a crucial tissue carries the abnormal cells." [source] In fact, according to a recent article in Nature, research on nerve cells in the brain has found they appear to naturally gain and lose chromosomes over time. Why they do so is still a mystery. The following conditions are all capable of having a "full version" or a "mosaic variation."

Klinefelter Syndrome (XXY Syndrome)

This is a chromosomal abnormality affecting males whereby they have sex chromosome makeup of XXY instead of just XY (referred to as 47,XXY). The extra X chromosome defines the condition, but there are also physical and hormonal characteristics. Body shape is usually described as "pear like." Most develop gynecomastia in puberty (male breasts), have underdeveloped testes of less than 14ml in volume, and lack development of normal male secondary sexual characteristics. Developmental delays and learning disabilities are sometimes present, though more recent studies have found nearly as many "hyper intelligent" people with Klinefelter Syndrome so the earlier data was most likely incorrect. 70% of Klinefelters males are sterile (though it is believed the 30% who are capable of spermatogenesis may actually be "mosaics" and not Klinefelter males).

In the early 1970's, researchers around the world sought to identify males having the extra chromosome by screening large numbers of newborn babies. One of the largest of these studies, sponsored by the National Institute of Child Health and Human Development (NICHD), checked the chromosomes of more than 40,000 babies.

Based on these studies, the XXY chromosome arrangement appears to be one of the most common genetic abnormalities known. . . .Although the syndrome's cause, an extra sex chromosome, is widespread, the syndrome itself - the set of symptoms and characteristics that may result from having the extra chromosome - is uncommon. Many men live out their lives without ever even suspecting they have an additional chromosome. (excerpted from "Understanding Klinefelter Syndrome: A Guide for XXY Males and Their Families," by Robert Bock, Office of Research Reporting NICHD, August 1993 U.S. Department of Health and Human Services. NIH Pub. No. 93-3202)

  • Discovery: First described in1942 by Dr. Harry Klinefelter
    47,XXY karyotype confirmed in 1956
  • Usually Diagnosed: during puberty
  • Frequency: 1 in 500 to 1000 births
  • More information:

    XXY Mosacicism: This is a condition is sometimes referred to as a "Klinefelter Associate" or "Klinefelter Variant" because it shares with it the common trait of an extra X chromosome. The difference is that the extra chromosome is not present in every cell throughout the person's body. About 10% of the cases where Klinefelters was initially diagnosed turn out to be "Mosaicism." The most common combination is that some cells will have normal male makeup of XY and others will be intersexed with XXY, referred to as 46,XY/47,XXY Mosaicism. Karyotypes of 46,XY/48,XXXY and 47,XXY/48,XXXY are also found within that ten percent. About 1% of cases are due to a structurally abnormal X in addition to a normal X and Y. Even fewer people have the karyotype of 47,XXY/46,XX. One of the problems with diagnosis is that the intersexed cells are not persistent throughout the individual's body. When doctors take a blood or tissue sample it is possible they may not gather any intersexed cells, or that the ones they do gather might be destroyed in the process of extracting the DNA to count the chromosomes. Furthermore, diagnosis by blood sample becomes even less accurate as the person ages because, for some unknown reason, intersexed blood cells are eliminated over time by the body. These factors can make a diagnosis elusive, especially in cases where the Mosaicism is present in only a small percentage of cells. The expression of Mosaicism is also highly variable. Some people show no obvious outwards signs of it, while others may present ambiguous genitalia at birth or developmental abnormalities at puberty.

    • Discovery: 1956-1960 by various researchers
    • Usually Diagnosed: depending on intensity diagnosis may be at birth, puberty, or in adulthood (usually during fertility testing)
    • Frequency: 1 in 1,666 births
    • More information:

Turner Syndrome (45, X): This is a chromosomal abnormality affecting females where they do not have 46 chromosomes, but instead have 45 with only a single X chromosome. Sometimes it is stated as an XO karyotyope (the "O" meaning there is no paired chromosome to the existing X). Turner's girls tend to have broadly spaced nipples and a generally flatter chest or no breast development (sometimes called a "shield chest"). Their waist tends to be wide and arms and legs are short in relation to the torso. Overall stature is usually quite short at less than 5 feet tall. Turner girls' faces are usually triangular in shape with a low hairline. There is minimal body hair distribution and genitals are usually also underdeveloped. Ovarian failure at puberty and sterility are also common. Approximately 15% of fetuses with Turner Syndrome spontaneously abort. In some cases the person might have 46 chromosomes, but the second X chromosome has no "short arm" called "Xp deletion." There is another variation called 45, X/46, XY Mosaicism where the individual has some cells that are of the Turner Syndrome karyotype and others that are of a male chromosomal makeup. In those cases the child may actually have undescended testes instead of ovaries.

  • Discovery: First described in 1938 by Henry Turner
    45, X karyotype confirmed in 1959
  • Usually Diagnosed: during childhood
  • Frequency: 1 in 1000 births
  • More information:

Triplo X (47, XXX): This is a condition affecting females, sometimes also called "hypofemale" or "super female." The physical manifestations of Triplo X are that the woman will usually have larger than average breasts with wider spaced nipples, a narrow (wasp) waist, wider hips than average, and a height of usually more than six feet. Some girls are also born with a "webbed neck" that is easily surgically corrected. This body type is sometimes describes as "Vampira" (the 1950's late night horror movie hostess) or, more recently, like that of the cartoon character Jessica Rabbit from the movie "Who Framed Roger Rabbit." By most standards Triplo X females are quite attractive, proving that a genetic/chromosomal abnormality need not be considered a "deformity." However, learning disabilities or developmental delays are not uncommon.

Diplo Y (47, XYY): Also sometimes called "Double Y" and "Polysomny Y." This is a condition affecting males who have an extra Y chromosome. Physical characteristics are often indistinguishable from an 46, XY male, though it is not uncommon for those with XYY karyotypes to be even more masculine than their average XY counterparts. Low, wide waists; narrow hips; broad, flat chest; wide shoulders; high hairlines; prevalent facial and body hair; and testes of more than 25ml in volume. It is also not uncommon for XYY males to have elevated testosterone levels responsible for the increased virilization they exhibit.

There is a popular belief that the extra Y chromosome predisposes these men to become criminals via aggression or sexual predation. There is no scientific evidence to justify the belief that XYY males are any more prone to criminal behavior than the general population.

NOTE: Triplo X and Diplo Y sex chromosome disorders are not generally considered "intersex conditions" since there is no "mixing" of female and male characteristics, but rather a exaggeration of female or male characteristics, respectively. They are mostly mentioned here because "mosaic versions" of them do exist and to illustrate the diversity of human sex chromosome combinations.


46, XX Male (Sex Reversal Syndrome): This is a chromosomal variation that is sometimes mistaken, initially, for Klinefelter Syndrome. People with this problem have a fragment of a Y chromosome with the "SRY testicular determining factor" translocated in their system. This causes the otherwise genetic female to develop physically as a male. 15% of those with this problem have undescended testes, 10% exhibit hypospadias. Generally 46, XX Males are shorter than Klinefelter males, but similarly display a lack of spermatogenisis (frequency unknown). [source: The Andrology Handbook, American Society of Andrology 1995. full text]

Figures for occurrence vary. One study cited that 1 in 5000 births has "full sex reversal," with "partial sex reversal" accounting for 1 in 1000 births. [source: Reaney, Patricia "Gene for human sex reversal syndrome identified," February 18, 1998 Reuters] Another source claims incidence is 1 in 20,000 births and that the cause can be attributed to:

  1. Mosaicism of XX and XXY cell lines
  2. Y;X translocation (SRY testicular determining factor transposed onto one X chromosome)
  3. Mutation of a gene downstream of SRY (testicular determining factor)

[source: "Sex Reversal," Clinical Molecular Genetics Society (U.K.), January 2000. full text]

AIS (46, XY Female): Until about 10 weeks of development in the womb, male and female embryos appear identical in external anatomy. the same structures then begin to differentiate as male under the influence of testosterone, or as female if the influence of testosterone is absent. In the presence of intermediate amounts of androgens - or partial insensitivity to the effects - the external genitals may develop in an "in-between" way. Androgen Insensitivity Syndrome is often abbreviated as AIS and is caused by a genetic error in the Androgen Recptor (AR) gene on the X chromosome. People with AIS have a male karyotype of 46, XY but may not develop a male phenotype.

There are two general categories for the "complete" and "partial" versions of AIS:

Complete Androgen Insensitivity Syndrome (CAIS) - the most pronounced form of the condition where the person's body is almost completely uninfluenced by androgens. Also sometimes called "Testicular Feminization Syndrome."

In CAIS there will still be no ovaries, fallopian tubes or uterus, and the vagina will be blind-ending and possibly short or absent. Female pubertal development occurs but there will be no menstruation and no possibility of conceiving/bearing children.

The undescended testes can result in an inguinal hernia in infancy and this is when AIS may be diagnosed in an apparently female child (approx. 50% of cases). Otherwise CAIS may not be discovered until puberty when there is a failure to menstruate (approx. 50% of cases).

Grade 7 - do not develop dark, course hair and often will not experience acne during puberty due to the complete insensitivity to androgens.

Grade 6 - may develop some dark, coarse hair because its growth is dependent on the effects of androgens. The nipples usually remain under-developed and pale in colour. The vagina may need to be lengthened or constructed before sexual intercourse is possible.

Partial Androgen Insensitivity Syndrome (PAIS) - a less pronounced form of the condition where the person's body is immune to androgen influence to varying degrees. Affected individuals have normal testes with normal production of testosterone and normal conversion to dihydrotestosterone (DHT), which differentiates this condition from 5-alpha-reductase Deficiency. Because the testes produce normal amounts of mullerian-inhibiting factor (MIF), also known as mullerian-inhibiting substance (MIS) or anti-mullerian hormone/factor (AMH/AMF) during gestation, affected individuals do not have fallopian tubes, a uterus, or proximal (upper) vagina. [source]

In PAIS, the external genitalia can be ambiguous, that is, intermediate in structure between male and female. Note that the structure of ambiguous external genitalia can be the same, whether the genetic sex and the sex of the gonads is male or female. The structure of the external genitals does not provide a way to determine whether the condition is PAIS of some other intersex condition. PAIS is also known as "Reifenstein Syndrome." There are basically five grades of PAIS:

Grade 5 - there may be partial fusion of the labia majora (outer vaginal lips), in which the posterior (back) portion of the labia form a web of tissue across the back part of the vaginal outlet.

Grade 4 - this fusion extends further forward, covering both the vaginal opening and the true urethral opening. The cavity formed by the fused labia, through which urine exits, is called a urogenital sinus.

Grade 3 - a more "masculinized" version of Grade 4 PAIS where the labia are completely fused, so that the urethral opening is at the base of the clitoris/penis. The fused labia may have a rugose, or wrinkled appearance and form a bifid, or double, scrotum. The fusion is then more properly called 'labio-scrotal fusion'. The phallus has the appearance of a large clitoris, or a small, bent, penis, bound down in structures called chordee. The chordee is formed from the same tissues that form the labia minora in the female and the frenulum of the penis and the tissues surrounding the urethra (corpus spongiosum) on the underside of the penis in the male. It is not true that the presence of chordee makes erections painful.

Grade 2 - the genital appearance is that of a male with hypospadias, that is, with a urethral opening located somewhere on the underside of the penis. There may be an open gutter running from the urethral opening to the glans of the penis. Assignment is usually male.

Grade 1 - No genital deformity or ambiguity. In almost all of these cases sex assignment at birth is male. The insensitivity to androgens is usually only detected at puberty when breast development (gynecomastia) occurs. The patient may or may not be infertile. This type of AIS is also known as "Mild AIS" (MAIS) and "Undervirilized Male Syndrome."

Sterility usually accompanies any AIS greater than Grade 3.

Definitive diagnosis is made by physical examination, internal scans, a chromosomal karyotyping, hormone testing, and genetic testing for a faulty AR gene on the X chromosome (called "mutation gene analysis) which is considered 95% accurate in detecting both CAIS and PAIS from buccal swabs. The genetic testing is slow (6 weeks or more) and expensive (not covered by most insurances).

  • Discovery: unclear. Hereditary pattern identified in 1912. Karyotype identified in 1937. Genetic cause identified in the 1980s.
  • Usually Diagnosed: at puberty or in adulthood (usually as part of fertility tests)
    Note: Doctors have often kept the truth about the diagnosis from their patients.
  • Frequency: unknown
    generally accepted estimate at 1 in 20,000 for all grades of AIS from Danish records
    other estimates range from 1:2,000 to 1:130,000 depending on grade.
  • More information:

5-Alpha Reductase Deficiency (5-ARD)- also known as "familial incomplete male pseudohermaphroditism type 2" and "pseudovaginal perineoscrotal hypospadias." It is an recessive genetic error resulting in the inability to convert testosterone into dihydrotestosterone (DHT). Since DHT is required for the normal masculinization of the external genitalia in utero, genetic males with 5-ARD are born with ambiguous genitalia (ie, male pseudohermaphroditism). In other words, the person may appear to physically be male, female, underdeveloped as either, or a mixture of both.

Effects range from infertility with normal male genital anatomy to underdeveloped male with hypospadias to predominantly female external genitalia. There is no uterus or fallopian tubes. Testes are intact, as are other male reproductive structures. Male internal ducts are present but may terminate in a blind pseudovaginal pouch. An underdeveloped prostate may be present, regardless of the appearance of the external genitalia.

Two genes coding for 5-alpha-reductase have been identified, each for a slightly different isoenzyme. The gene for 5-alpha-reductase type 1 has been determined to be on chromosome 5. Its product is expressed only in nongenital skin and liver at low levels from the time the individual is aged 3 years to puberty, at which time enzyme expression is measurable in sebaceous glands and scalp. Linkage analysis has demonstrated that the type 1 enzyme is unrelated to the clinical syndrome of 5-ARD. The other isoenzyme, 5-alpha reductase type 2, determined on chromosome 2, correlates with clinical symptoms. It is expressed in high levels in the prostate and other androgen-sensitive tissues. Interestingly, partial virilization of males with 5-ARD occurs at puberty and may be attributable to the rise in type 1 enzyme activity at that time.

More than 20 different mutations of this gene have been reported in people with clinical and biochemical evidence of the enzyme deficiency. The presentation of symptoms by most people is variable, even within the same family.

Congenital Adrenal Hyperplasia (CAH) - The term congenital adrenal hyperplasia encompasses several autosomal (single chromosome) recessive disorders that share complete or partial deficiency of an enzyme involved in cortisol or aldosterone synthesis. [only the CYP21, CYP17, and StAR forms of CAH are discussed below] All disorders of this group share the common feature of a deficiency or relative defect in cortisol or aldosterone synthesis resulting in some degree of cortisol or aldosterone deficiency, or both.

The phenotype (whether the person looks male or female) depends on which particular protein is affected and the severity of the mutation or degree of deletion of the particular gene encoding for the protein involved in steroidogenesis. The appearance of people with CAH can vary from no apparent effect (clinically referred to as occult or cryptic adrenal hyperplasia) to a mild form that becomes obvious during adolescence or adulthood (nonclassic adrenal hyperplasia), to severe forms diagnosed in infancy, with or without virilization and salt wasting (classic adrenal hyperplasia). CAH activity is generally divided clinically into a simple virilizing (masculinizing) form and a salt-wasting form.

Females with some forms of CAH have ambiguous genitalia at birth (classic virilizing adrenal hyperplasia) or become virilized in later childhood (simple virilizing adrenal hyperplasia) or in adolescence and adulthood (nonclassic virilizing adrenal hyperplasia).

Males with the "CYP21" form of CAH are not generally identified as infants because their genitalia appear normal. If the chromosomal defect is severe, resulting in salt wasting, these male infants are seen at 1-4 weeks of age because of failure to thrive, recurrent vomiting, dehydration, and shock. Some male infants are initially misdiagnosed with gastroenteritis or pyloric stenosis. If not diagnosed in infancy, they are often diagnosed in later childhood because of early pubic hair and/or phallic enlargement accompanied by accelerated linear growth and advancement of skeletal maturation.

Males with "CYP17" deficiency generally have ambiguous genitalia or female genitalia because of inadequate testosterone production in the first trimester of fetal life.

A female with "CYP17" deficiency appears female at birth, but does not develop breasts or menstruate in adolescence because of inadequate estradiol production.

Males with StAR deficiency (lipoid adrenal hyperplasia) have female or ambiguous genitalia. Females have normal female genitalia. Genetic females who survive infancy do develop breasts and menstruate at puberty.

Sex phenotype, then, varies along the full continuum from "normal male" to "normal female," with the possible added complication of metabolic problems which upset serum sodium balance. The metabolic effects of CAH can be counteracted with cortisone.

  • Discovery: 1865 Luigi DeCrecchio. Treatment devised in 1950.
  • Usually Diagnosed: birth or early childhood
  • Frequency:
    Cryptic: 1 per 60 in the general population*
    Non-Classic: 1 in 27 to 1 in 100
    Classic: 1 per 13,000 to 1 per 16,000

    CYP21 accounts for 90% of all cases
    CYP11 accounts for 5-8% of all cases*

    * CYP21 errors are present in as many as 1 out of 3 people of Ashkenazi Jewish heritage. CYP11 are more often observed in people of Moroccan, Iranian, or Jewish descent.
  • More information:


Progestin Induced Virilization (PIV) - Progestin is a drug which was administered to pregnant women in the 1950's and 1960's and is converted to an androgen by the prenatal XX fetuses' metabolism. Sometimes the genitals of fetuses affected by progestin are virilized with effects ranging from enlarged clitoris to the development of a complete phallus and the fusing of the labia. In all cases ovaries and uterus or uterine tract are present, though in extreme cases of virilization there is no vagina or cervix, the uterine tract being connected to the upper portion of the urethra internally. The virilization only occurs prenatally, and feminizing puberty occurs due to normally functioning ovaries.

DES Exposure - DES is a synthetic estrogen that was given to millions of pregnant women between 1937 and 1971 because the medical profession believed it would help prevent miscarriage and insure a healthy full term pregnancy. A 1957 advertisement claimed desPLEX® would "prevent ABORTION, MISCARRIAGE and PREMATURE LABOR…recommended for routine prophylaxis in ALL pregnancies…" This was only one of numerous brand names that DES (diethystilbestrol) was sold under.

DES did not work. In fact, the unfortunate use of this drug has resulted in severe risks and consequences to the health of many of the women who took the drug, as well, the daughters and sons whom they bore.

DES Sons (46, XY DES) - DES sons are those who's mothers took DES during pregnancy. Although, most DES sons will not experience adverse health effects from this exposure there are certain signs that should be watched for by a medical professional.

The effects faced by DES sons include:

  • Hypospadias
  • Meatal stenosis- a narrowing of the opening of the penis.
  • Epididmymal cysts- the most common abnormality, non-cancerous cysts located on the back of the testicles.
  • Testicular problems- undescended or small testicles, which are visible at, birth. Men with this condition are at increased risk of testicular cancer.
  • Microplallus (also called Micropenis)
  • Testicular varicoceles- an irregularly swollen or varicose vein on the testicle.

Previous studies do not show a correlation between DES and fertility problems in men. Testicular self-exam and yearly check-ups are important for all men, but particularly for DES sons.

DES Daughters (46, XX DES) - Contrary to prior belief, women who were exposed to DES before birth also experience problem. They require special care during pregnancy because of an increased risk of problems such as ectopic pregnancy and premature labor and delivery. However, with proper care most women can achieve and maintain healthy full term pregnancies. Some DES exposed women may have an increased risk of fertility problems, however getting pregnant is not difficult for most women, and routine infertility evaluation is not usually necessary. The greatest risk to DES daughters is an increased risk for a rare form of cervical or vaginal cancer called clear cell carcinoma. Abnormal cell changes on the cervix may occur more frequently among this group of women and they should be treated in most cases. DES daughters need regular pelvic exams at all ages. The pelvic exam for DES daughters is slightly different from the normal pelvic exam because it includes a separate Pap smear of the upper vagina. If DES-related changes are detected during a pelvic exam, it may be necessary to have pelvic exams more than once a year.

  • Discovery: circa 1970
  • Usually Diagnosed: at any stage of life problems may be discovered that can be linked to DES exposure before birth or as children.
  • Frequency: unknown
  • More information:

Environmental Estrogen Exposure - Although DES is no longer given to pregnant women, a new problem has been identified. There are a number of industrial chemicals and pesticides like DDT and PCBs that mimic estrogenic activity (called pseudo-estrogens). Many of these chemicals, although either discontinued or restricted in use, have found their way into the ecosystem. There is a growing body of evidence concerning how these "environmental estrogens" feminize the male reproductive systems across almost all species exposed to them - including human beings. Obviously those exposed to these chemicals in utero or after birth are at risk, though the effects are far more pronounced on a developing fetus than on an adult.

  • Discovery: Allen, E. and E.A. Doisy. 1923. DDT's estrogenic effect identified in 1950.
  • Usually Diagnosed: at any stage of life problems may be discovered that can be linked to Environmental Estrogen exposure before birth or later in life.
  • Frequency: unknown
  • More information:


ON THIS LIST - This list of Intersex Conditions is far from comprehensive. There are simply too many variations, causes, and presentations to create a complete catalog of them on this site. For more detailed information click on the "More information" links following each condition.

It should be pretty obvious that anyone who taught you that men have a penis and testicles and XY chromosomes and women have a vagina and ovaries and XX chromosomes, at best, oversimplified the diversity of biological sex.

ON CITED FREQUENCIES - The prevalence of each condition listed may not reflect the true frequency of it in the general population. Estimated frequencies are based on diagnosed, recorded cases identified in a clinical setting. It is likely, especially for milder forms of each condition, that there is a significant portion of cases that are misdiangosed or go undiagnosed altogether. Frequencies are also affected by the databases and recording methodologies used, which vary widely from one locale to another. For example, the estimate for Androgen Insensitivity Syndrome at 1 in 20,000 comes from a Danish database of genetic anomolies. Denmark has a national healthcare system with standardized reporting to a government maintained database. And the number refers to all incidence of AIS without distinction of grade. The American prevalence of 1 in 60,000 is based on girls identified as having Complete Androgen Insensitivity Syndrome (grades 7 or 8) who were discovered during routine hernia operations. Until that point those girls were assumed to be genetic females. Partial Androgen Insensitivity Syndrome may be mild enough to go undiagnosed, or may be misdiagnosed as another problem. The Intersex Society of North America quotes a frequency of 1 in 130,000 for PAIS cases. However, that only represents those cases that were clinically identified. It is likely mild PAIS forms (especially grade 1) are quite common but are never clinically identified.

The most comprehensive study of chromosomal anomolies, the National Institute of Child Health and Human Development (NICHD) multi-year study in the early 1970's of some 40,000 infants, found an incidence of 1 in 500 to 1 in 1000 for XXY karyotypes. Follow up studies of reported clinical identification of XXY conditions indicated that only about 2% of such people were ever formally diagnosed. This either indicates that, while XXY karyotypes are quite common adverse effects are relatively rare, or doctors are overlooking or misdiagnosing the conditions, or the bulk of people with XXY karyotypes never present themselves to a doctor.