What Is Intersex?

When Sexual Anatomy Doesn't Align With the Assigned Sex

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Intersex is a general term used to describe anyone with reproductive or sexual anatomy that doesn't align with the traditional definitions of "male" or "female."

The term "intersex" is not related to a person's gender (how they see themselves in relation to the society's definition of "male" or "female") but rather to the sexual characteristics a person is born with.

This may include their external genitals (like a vagina or penis), internal reproductive organs (like ovaries or a uterus), or sex chromosomes (the genetic material that determines a person's biological sex).

Intersex is neither a type of sexual orientation nor a medical problem. It is a naturally occurring variation that may or may not be apparent and may or may not pose any health concerns.

Mother holding her baby hand
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This article explores what it means to be intersex and gives examples of some of the more common intersex variations. It also looks at some of the challenges faced by intersex people, including discrimination and medical practices that may pose more harm than good.

What It Means to Be Intersex

Intersex describes naturally occurring variations in biological sex characteristics. These differences may be apparent at birth or may not be recognized until later in life. Oftentimes, a person will go through life fully unaware that they have an intersex variation.

Intersex is both a biological state and, in recent years, a group identity for people who have been historically stigmatized for being born with bodies that do not align with the binary definition of "boy/girl," "man/woman," or "male/female."

These abuses have led in recent years to the establishment of the intersex movement which advocates for the human rights of intersex people.

How Common Is Intersex?

Intersex births are more common than people think. A 2019 study in the Journal of the Endocrine Society suggests that 1.3 of every 1,000 babies are born with identifiable intersex traits. Other studies suggest that the actual intersex rate, whether readily identified or not, is closer to 2%.

Causes of Intersex Variations

Many intersex births are due to variations in sex chromosomes that you inherit from your parents. Typically, your mother will contribute an X chromosome, while your father will contribute either an X or Y chromosome.

Many intersex people have chromosomes combinations that are different from XY (typically associated with males) or XX (typically associated with females). These combinations can lead to variations in external genitals, internal sex organs, and sex hormones (including testosterone and estrogen).

But not all intersex births are caused by chromosome variations. In some cases, the sex characteristics of a fetus will change if testosterone or estrogen levels are excessively high or excessively low. These, too, may be the results of genetics but may also be caused by medical conditions, drugs, or toxins that disrupt how hormones are produced or processed.

There are four broad intersex categories, each of which has multiple variations and different possible causes:

46, XX Intersex

This is a person who has XX chromosomes and ovaries typically regarded as "female" but external genitals typically regarded as "male." This is most often caused when a female fetus has been exposed to excess male hormones before birth (such as can occur if the mother has a pituitary tumor or is exposed to testosterone during pregnancy).

46, XY Intersex

This is a person who has XY chromosomes but external genitalia that are typically regarded as "female." This is most often due to low levels of testosterone that influence the development of male sexual organs. It may also be due to the lack of enzymes used to process testosterone.

True Gonadal Intersex

This is a person who has both ovaries and testicles, either with XX chromosomes, XY chromosomes, or both. The cause of most cases of true gonadal intersex is unknown, although some instances are thought to be the result of environmental toxins.

Complex or Undetermined Intersex

This is a person who does not have differences between external or internal organs but may experience variations in sexual development due to altered hormone levels. Many of these variations are the result of having an extra X or Y chromosome or having only an X chromosome.

Types of Intersex Variations

There are at least 60 categories of conditions that meet the definition of intersex. Within these categories, there is a lot of variation in sex characteristics.

Some intersex variations are relatively common. This includes Klinefelter syndrome which occurs in one of every 500 to 1,000 male births and congenital adrenal hyperplasia which occurs in one of 1,000 female births.

Klinefelter Syndrome

Klinefelter syndrome (also known as XXY syndrome) is a variation caused by the addition of an X chromosome to the XY chromosomes in males.

People with Klinefelter syndrome often have decreased testosterone production, referred to as primary hypogonadism. As a result, they may have a short stature, low sperm count, and an increased risk of infertility.

Some people with Klinefelter syndrome have hypospadias (in which the opening of the penis is on the underside of the penis rather than the tip). Others have micropenis (an abnormally small penis) or gynecomastia (the abnormal enlargement of male breast tissues)

Studies indicate that most people with Kleinfelter syndrome are unaware of their intersex variation. Only around 25% are ever officially diagnosed, most often when they are in their 30s.

Androgen Insensitivity

Androgen insensitivity is an inherited condition in which your body has a complete or partial inability to respond to testosterone and other male hormones (called androgens).

People with androgen insensitivity have XY chromosomes associated with males but either external genitals associated with females or genitals that are not typically male or female.

There are two categories of androgen insensitivity:

  • Complete androgen insensitivity: These individuals are typically born with a vulva and a clitoris but no uterus. They may also have undescended testicles as well as a partial or complete vagina.
  • Partial androgen insensitivity: This is when a person has a limited ability to respond to androgens, which can lead to many different variations including hypospadias, micropenis, clitoromegaly (an abnormally large clitoris).

Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) is an inherited condition that affects the adrenal glands that are responsible for producing many different hormones. CAH can occur in people of either sex but generally does not cause symptoms in males.

People with CAH lack one of the key enzymes needed to make certain hormones. This can lead to the underproduction of certain hormones (like the stress hormone cortisol) and the overproduction of androgens, including testosterone.

In people with the XX chromosomes, CAH can lead to the enlargement and fusion of the clitoris and labia, closing the opening of the vagina. While the person will have ovaries and a uterus, the external genitals may not be regarded as either male or female.

Congenital adrenal hyperplasia can lead to early puberty, rapid body growth, and the premature completion of growth (which results in short stature).

Impact of Discrimination

There have historically been social and cultural consequences to being an intersex person. In the past, many such individuals were referred to as "hermaphrodites" or "eunuchs" and subject to scorn, abuse, discrimination, and physical harm.

Even in medicine, intersex variations are often referred to as disorders of sexual development (DSDs), suggesting that they are problems meant to be corrected.

It is for these reasons that the "I" in "LGBTI" references intersex people even though being intersex is not a sexual orientation. As with other groups that fall under the LGBTI umbrella, intersex people are largely marginalized and subject to stigmatization.

Intersex is not the same thing as being gender fluid (having a gender identity that can change) or transgender (having a gender identity different from the sex you were assigned at birth). Intersex describes a biological variation that may or may not have any health consequence.

Changing Attitudes and Practices

Human rights advocates are placing increasing scrutiny on harmful practices and discrimination against intersex people. These abuses can start at birth when parents and medical professionals decide to assign a sex—boy or girl—to an intersex child. In some cases, this will require life-long hormonal therapy to maintain the assigned gender identity.

Although practices like this were common (and even once considered "beneficial" to a child), advocates contend that they treat intersex as a medical problem rather than as a natural variation of an otherwise healthy body.

Today, more and more people regard gender assignment surgery on newborns as unethical, depriving a child of autonomy over their own body and identity.

Studies have shown that discrimination can take a toll on the mental health of intersex people who have higher rates of alcohol and substance abuse than the general population.

Mental Health in Intersex People

A national survey published in PLoS One reported that 41% of intersex people reported that their mental health was "poor," while 61% and 62% met the clinical diagnosis of depression and anxiety respectively. By contrast, only 15% of those surveyed reported that their physical health was "poor."

By changing attitudes that intersex bodies are "abnormal," it is hoped that the abuse, abandonment, and discrimination commonly experienced by intersex people can be reversed.


Intersex is an umbrella term for any variation in reproductive or sexual anatomy that doesn't align with societal definitions of being "male" or "female."

There are many ways to be intersex. They may be due to variations in sex chromosomes or genetic changes that affect the body's production of or response to hormones. Sometimes, intersex traits are identified at birth, while others are not identified until later in life (or not at all).

Intersex people are often subject to discrimination and harmful practices that rob them of autonomy over their own bodies. This includes performing gender assignment surgery at birth, the practice of which infers that intersex people are abnormal despite having healthy bodies.

A growing intersex movement aims to changes those attitudes by raising awareness and advocating for the rights of intersex people.

A Word From Verywell

If you or someone you love is intersex and are struggling with discrimination, isolation, or abuse, connect with a support group that fully understands what you are going through. InterAct, a non-profit organization supporting intersex youth, maintains a list of support and advocacy groups across the United States that can help.

Frequently Asked Questions

  • Can an intersex person reproduce?

    It depends. In many cases, people who are intersex are infertile, but that is not always true. If a person has a penis and produces sperm, they may be able to father a child. An intersex person who has a uterus and ovaries may be able to become pregnant and carry a child to term. 

  • Are intersex people asexual?

    Not necessarily. The two terms are used to describe different things. Intersex has to do with anatomy, genes, and hormones, while asexual refers to a person's sexual orientation.

    Asexual is a term that describes people who do not experience sexual attraction or have very little interest in sexual activity. Some people who are intersex identify as asexual, but many also do not.

  • What does hermaphrodite mean?

    The dictionary defines hermaphrodite as a person or animal having both male and female sex organs. The term is no longer used to refer to people, however, and is considered offensive.

    In science, the term is used to describe organisms that have both female and male sex organs. It is more commonly used to define plants than animals. Hermaphroditic animals are primarily invertebrates, like barnacles, slugs, and worms.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Aydin BK, Saka N, Bas F, et al. Frequency of ambiguous genitalia in 14,177 newborns in Turkey. J Endocrine Soc. 2019 Jun;3(6):1185-95. doi:10.1210/js.2018-00408

  2. Blackless M, Charuvastra A, Derryck A, Fausto-Sterling A, Lauzanne K, Lee E. How sexually dimorphic are we? Review and synthesis. Am J Hum Biol. 2000:12:151-66. doi:10.1002/(SICI)1520-6300(200003/04)12:2<151::AID-AJHB1>3.0.CO;2-F

  3. American Academy of Pediatrics. Explaining disorders of sexual development and intersexuality.

  4. MedlinePlus. Intersex.

  5. National Center for Advancing Translational Sciences. Klinefelter syndrome.

  6. National Organization for Rare Disorders. Congenital adrenal hyperplasia.

  7. Calogero AE, Giagulli VA, Mongioì LM, et al. Klinefelter syndrome: cardiovascular abnormalities and metabolic disordersJ Endocrinol Invest. 2017;40(7):705-712. doi:10.1007/s40618-017-0619-9

  8. Planned Parenthood. What is intersex?

  9. Substance Abuse and Mental Health Services Administration. Identifying mental health and substance use problems of children and adolescents: a guide for child-serving organizations.

  10. Rosenwohl-Mack A, Tamar-Mattis S, Baratz AB, et al. A national study on the physical and mental health of intersex adults in the U.S. PLoS One. 2020;15(10):e0240088. doi:10.1371/journal.pone.0240088