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Types of intersex


The sexual differentiation of the human embryo is an extremely important stage during the development of pregnancy. It determines the biological sex of the person and the subsequent sexual development of the person.

In the event that the pregnancy takes place without any alteration, the sex of the embryo will be feminine “by default”, carrying out a series of chain reactions at the genetic and hormonal levels so that the embryo develops as a male.

But there are a series of cases, in which certain causes, sometimes unknown, cause this process to be altered, giving rise to phenomena such as hermaphroditism or intersexuality.

What is intersexuality?

At a general level, intersexuality is an expression used in biology to refer to those organisms that have reproductive organs corresponding to both sexes . Specifically, except humans, those creatures or organisms listed as hermaphrodites are trained to produce sex cells, also called gametes, both male and female.

With regard to people, some cases similar to hermaphroditism have been described, which are determined as pseudohermaphroditism since there is no possibility of reproduction of both forms. Even so, from a gender perspective, the most appropriate term to describe people with these characteristics is intersexual.

An intersex person has a modification in their body, due to this modification that person has a divergence between their genitals and their sex ; being able to present genetic and phenotypic characteristics belonging to both sexes, in variable proportions.

A widely held myth is the belief that an intersex person simultaneously possesses fully developed and functional sexual and reproductive organs , both male and female . However, what characterizes intersexuality is that, unlike the hermaphroditism seen in other animals, an intersexual person has a genital indeterminacy that can occur in different degrees and that can manifest during any stage of his life.

Types of intersexuality

Human intersexuality can be divided into several categories according to the causes that originated it.

1. Intersexuality 46, XX

In this type of intersexuality the person is born with the chromosomal characteristics of a woman and ovaries of the female sex , but their phenotype, or external appearance of the genitals, is male.

This phenomenon has as its most common cause the excessive exposure of the fetus to male hormones . In this way, during pregnancy the labia majora come together and the clitoris increases in size until it reaches the appearance of a penis. As regards the rest of the female reproductive organs, such as the uterus or the fallopian tubes, they usually develop correctly.

Some of the causes why the fetus is exposed to this amount hormones can be:

  • Congenital adrenal hyperplasia , this being the most probable cause.
  • Consumption, by the mother, of male hormones during pregnancy.
  • Ovarian tumors that produce an excess of male hormones.
  • Aromatase deficiency in the fetus , responsible for transforming male hormones into female ones. The effects of this deficiency can begin to be noticed at puberty, during which it is possible that masculine characteristics begin to appear.

2. Intersexuality 46, XY

This alteration would be contrary to the previous one. In these cases the person has male chromosomes , however the genitals are visibly feminine or imprecise in any case.

As for the formation of the internal reproductive system, the testicles may have developed normally, but cases have been described in which they suffer from a malformation or even fail to form.

For a correct development of the male genitalia, both internal and external, it is necessary a good stability of both types of  sex hormones . Some of the reasons why this is sometimes not the case are:

  • Malformation of the testicles : if the testicles do not develop correctly, the production of male hormones can be reduced, leading to subvirilization.
  • Alterations in the formation of testosterone : lack or deficit in some of the enzymes responsible for producing this hormone properly.
  • Deficiency of 5-alpha-reductase : this deficit is the main cause of intersexuality 46-XY, causing the well-known syndrome of androgen insensitivity (SIA). By which people with abnormal testicles, generate correct proportions of testosterone, however the recipients of these do not work properly.

3. True gonadal heterosexuality

In these cases the person possesses in the same way both ovarian tissue and testicular tissue . This phenomenon was known as true hermaphroditism, since the person can have this tissue in the same gonad, which is known as “ovotestículo”, or have an ovary and a testicle at the same time.

At the chromosomal level, true gonadal intersexuality can occur in both XX and XY , and the external genitalia can be revealed as masculine, feminine or ambiguous. The causes of this type of intersexuality are still unknown in humans.

4. Complex intersex disorders or indeterminacy of sexual development

The latter category includes a series of disorders in which there is no difference between internal and external sexual structures . Rather, alterations occur in sex hormone levels and in overall sexual development.

These cases include the 45-XO disorders, in which only one X chromosome exists; and the 47-XXY or 47-XXX, in which the person is born with extra sex chromosome.


The symptoms of intersexuality are variable in terms of degrees and assiduity, depending on the causes that underlie this.

The main symptoms are:

  • Increase in the size of the clitoris or clitoromegaly
  • Micropene
  • Genital ambiguity
  • Joint of the lips
  • No descent of the testicles in male children, with the possibility that they are ovaries
  • Lip masses in girls that can be testicles.
  • Apparently unusual genitalia
  • Hypospadias or anomaly by which the orifice of the penis is located in another place or the urethra has the opening in the vagina.
  • Lack or delay of puberty
  • Abrupt changes in puberty

Diagnostic tests and intervention

For the realization of a good diagnosis of intersexuality, and a possible subsequent treatment, it is necessary to carry out a series of tests by medical personnel. These are:

  • Analysis of hormone levels
  • Chromosomal analysis
  • Hormone stimulation tests
  • Molecular tests
  • Genital endoscopy
  • Ultrasonography or magnetic resonance that allows to verify the existence of internal sexual structures

Medical and psychological intervention

Given the complexity of these alterations and the complexity of human sexual development, it is necessary the performance of a multidisciplinary teamthat works both with the person and with the family, both at a medical level and at a psychological level.

Traditionally, the procedure to be followed was the assignment of sex according to the external genitalia , instead of taking into account the chromosomal configuration, leaving no room for ambiguity and recommending an early surgery in which the testicular or ovarian tissue was removed. it would agree

However, with the passage of time, a large part of the medical community observed that this procedure caused great interference in the sexual development of the person , which is why the point of view has now been modified as to how to intervene in cases of intersexuality

Currently, both the chromosomal and hormonal elements are taken into account, as well as the psychological and behavioral aspects that shape the sexual identity; taking time when performing any surgery and involving the person in the choice of their sex.

With the support, understanding and adequate professional intervention, the prognosis of intersex people is extremely positive, being able to develop their own sexuality, healthy and without complications.


Kolodny, Robert C.; Masters, William H.;Johnson, Virginia E. (1979). Textbook of Sexual Medicine (1st ed.). Boston: Little, Brown and Company. ISBN 978-0-316-50154-5.

Intersex: MedlinePlus Medical Encyclopedia” Retrieved 25 March 2019.

Kamijo, H.; Narita, O. (November 1997). “[Female pseudohermaphroditism]”. Nihon Rinsho. Japanese Journal of Clinical Medicine55 (11): 2925–2929. ISSN 0047-1852. PMID 9396289

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