What is intersex?

Defining intersex: an image of a magnifying glass over a plus symbolThis page presents a range of working, Australian and international definitions of intersex.

Working definition

As a simple working definition of intersex, Intersex Human Rights Australia uses the following statement:

Intersex people are born with physical sex characteristics that don’t fit medical and social norms for female or male bodies.

It is worth taking time to recognise that this definition does not specify a sex, nor specific about particular biological characteristics, legal sex classification, birth sex assignment, gender, gender identity or sexual orientation. Intersex people do not share any identity, we are a very diverse population. Intersex people old enough to freely express an identity can be heterosexual or not, and cisgender (identify with sex assigned at birth) or not. If you’re looking for a word meaning non-intersex, that word is endosex.

Intersex traits include a wide range of different underlying variations. These can be determined prenatally, at birth, during puberty and at other times, such as when trying to conceive a child. Each trait has its own characteristics and differing degrees of expression. The term intersex is best described as an umbrella. Individual people with intersex variations use a variety of different terms, including being intersex, having an intersex variation or condition, or naming specific traits. It is important to respect individual choices, but also to acknowledge that people make choices about terminology based on what we learn, and also in response to misconceptions and risks of stigmatisation.

Darlington retreat

Members of Australian and Aotearoa/NZ intersex organisations, and independent advocates, in Darlington, Sydney, in March 2017. Read our joint Darlington Statement. Photo courtesy of Phoebe Hart.

Earlier definition

We have discontinued use of an earlier definition of intersex, below, even though it is based on that in the Sex Discrimination Act (Cth), for two reasons. Firstly, because it is primarily based on a model of deficits, what we don’t have, or what we lack, Secondly because, even though it refers to physical features, it has frequently and incorrectly been imputed to mean something about identity or sex classifications:

Intersex people are born with physical, hormonal or genetic features that are neither wholly female nor wholly male; or a combination of female and male; or neither female nor male.

International definitions

Internationally, definitions have converged in recent years, and shifted towards a model based on human rights law rather than medical definitions. This definition is simply expressed in a 2019 background note on intersex by the Office of the UN High Commissioner for Human Rights:

Intersex is an umbrella term used to describe a wide range of innate bodily variations of sex characteristics.
Intersex people are born with physical sex characteristics (such as sexual anatomy, reproductive organs, hormonal patterns and/or chromosomal patterns) that do not fit typical definitions for male or female bodies

A shorter Fact Sheet with a closely similar definition is available in a number of languages via the Free & Equal campaign.

In 2016, the Asia Pacific Forum of National Human Rights Institutions published a manual on sexual orientation, gender identity and sex characteristics, defining intersex as:

An umbrella term used to describe people born with sex characteristics (including genitals, gonads and chromosome patterns) that do not fit typical binary notions of male or female bodies.

Earlier definitions include, for example, a definition by the Council of Europe, in a 2013 explanatory memorandum to Resolution 1952 on children’s right to physical integrity:

The term “intersex” refers to atypical and internal and/or external anatomical sexual characteristics, where features usually regarded as male or female may be mixed to some degree. This is a naturally occurring variation in humans and not a medical condition. It is to be distinguished from transsexuality, a phenomenon where someone has an evident sex, but feels as if he or she belongs to the other sex and is therefore ready to undergo a medical intervention altering his or her natural sex.

ABC’s You Can’t Ask That season 4 episode 3 focuses on intersex people. Watch in ABC iView

Australian definitions

In the 2015 report, “Resilient Individuals: Sexual Orientation Gender Identity & Intersex Rights 2015“, the Australian Human Rights Commission defines intersex as:

The term ‘intersex’ refers to people who are born with genetic, hormonal or physical sex characteristics that are not typically ‘male’ or ‘female’. Intersex people have a diversity of bodies and identities.

The Commonwealth Sex Discrimination Amendment (Sexual Orientation, Gender Identity and Intersex Status) Act 2013 added the following definition to federal anti-discrimination law:

intersex status means the status of having physical, hormonal or genetic features that are: (a) neither wholly female nor wholly male; or (b) a combination of female and male; or (c) neither female nor male.

Note that this definition deliberately contains no barrier preventing people perceived to be intersex from gaining protection from the law. The definition of “intersex status” is also differentiated from both “sex” and “gender identity”.

2013 Australian Commonwealth guidelines on sex and gender recognition underwent minor revision in 2015. Previously the introduction to the guide stated:

An intersex person may have the biological attributes of both sexes or lack some of the biological attributes considered necessary to be defined as one or the other sex. Intersex is always congenital and can originate from genetic, chromosomal or hormonal variations. Environmental influences such as endocrine disruptors can also play a role in some intersex differences. People who are intersex may identify their gender as male, female or X.

Now the guide states:

12. The term intersex refers to people who are born with genetic, hormonal or physical sex characteristics that are not typically ‘male’ or ‘female’. Intersex people have a diversity of bodies and gender identities, and may identify as male or female or neither.

This is contradicted somewhat by the definition of ‘X’, a third gender classification, as “Indeterminate/Intersex/Unspecified“. In September 2015, OII Australia, together with the National LGBTI Health Alliance, Transgender Victoria and other organisations formally requested that ‘X’ be redefined as “non-binary” in the guidelines.

The three gender options comprise the full range of options available according to the guidelines, but some intersex people have other identities not covered in the guidelines.

Bonnie Hart, Morgan Carpenter, a parent and a clinician talk with SBS. Watch on SBS website. Medical interventions still continue on health infants and children, read follow-up article at SBS

Medical definitions

It is important to note that an invitation-only meeting in Chicago in 2006 reported in Summary of Consensus Statement on Intersex Disorders and Their Management coined a controversial new term, “Disorders of Sex Development” aimed at replacing the term intersex in medical settings:

“disorders of sex development” (DSD) is proposed to indicate congenital conditions with atypical development of chromosomal, gonadal, or anatomic sex.

Stated due to “[a]dvances in molecular genetic causes of abnormal sexual development and heightened awareness of the ethical and patient-advocacy issues“, this new language reasserted medical authority in the light of successful intersex activism that identified our issues as human rights, and is strongly contested. It pathologises intersex variations as inherently disordered, and according to Morgan Holmes, “reinstitutionalises clinical power to delineate and silence those marked by the diagnosis“. Intersex Human Rights Australia opposes use of the term DSD because of these factors.

Since 2013, a range of medical and scientific papers have employed a variety of language such as “intersex“, “intersex traits“, “diverse sex development“, and “diverse sex development, also known as intersex (DSDI)“.

The World Health Organization’s Genomic resource centre gives an undated definition:

Intersex is defined as a congenital anomaly of the reproductive and sexual system.

A 2014 joint paper on “Eliminating forced, coercive and otherwise involuntary sterilization” by the World Heath Organization, OHCHR, UN Women, UNAIDS, UNDP, UNFPA and UNICEF states simply that “Intersex persons …[are] born with atypical sex characteristics.” The report makes a series of recommendations aimed at changing current clinical practices, improving health outcomes and human rights, and providing reparations.


If you want a word for “non-intersex”, that word is “endosex”, for “within” or internal to sex characteristic norms. Some people may use the term “dyadic” with the same intent.

More information

This page is not intended as an introduction to intersex.

This page is periodically updated.