What is intersex?
Intersex is an umbrella term for people whose reproductive organs, sexual anatomy or chromosome patterns differ from the biological definition of male or female. There are many ways someone can be intersex as it involves a spectrum of reproductive characteristics. Being intersex is a natural variation in humans, it does not mean there is something wrong.
Intersex traits can relate to
- Genitalia
- Internal anatomy
- Hormones
- Chromosome combinations different to XY (male) and XX (female).
Some intersex people have both ovarian and testicular tissue, while others have atypical female or male genitalia, or male/female genitalia with variations in their internal organs and/or hormones. Some intersex conditions may be related to underlying concerns that might require medical care, but people who are intersex are generally as healthy as those who are not.
How common are intersex conditions?
An estimated 1.7 per cent of babies are born with intersex conditions, although many variations are not apparent at birth. About one in 2,000 newborns have genital differences that involve a sex differentiation specialist being consulted. Others are identified later in life, sometimes not until puberty or adulthood.
Causes of intersex
Intersex traits can vary considerably and have a complex range of causes. Most are random but some are genetic. Chromosome variations can happen randomly and spontaneously during conception due to egg cells or sperm cells. This means a child may not have the typically male (XY) or female (XX) chromosomes and instead have a combination such as XXY or XYY. Some intersex people do fit into either the XX or XY category but develop female anatomy on the outside and male anatomy on the inside. In many cases, the cause is not determined.
Types of intersex conditions
Intersex traits generally fit into three categories, including
- 46, XX intersex: Female chromosomes and ovaries but external genitals appear male. This can be caused by exposure to excess male hormones before birth.
- 46, XY intersex: Male chromosomes but external genitals are incompletely formed, ambiguous or female. Testes may be normal, malformed, or absent. May be caused by testosterone issues and other foetal development variations.
- Sex chromosome intersex: Can involve a range of chromosomal variations that affect sex development. They don’t cause a discrepancy between internal and external genitalia but possible problems with sex hormone levels and overall sexual development.
Misconceptions
Gender identity refers to a fundamental sense of belonging and self-identification of being female, male, both, or something other than female or male. It does not necessarily correspond to the sex assigned or presumed at birth.
Sexual orientation is the sex of the person to whom one is sexually attracted. It may include heterosexual, bisexual, homosexual, pan-sexual, or asexual.
Being intersex is not the same as being transgender, which is when a person does not identify with their biological sex.
What happens when someone is born intersex?
Historically, medical research aimed to explain why people were intersex and how it could be ‘fixed’. A baby with intersex traits was usually assigned male or female, which often resulted in surgery or medication. It is now more widely understood that such difference does not mean physical makeup needs to be changed.
More people believe that those born with intersex traits should not face unnecessary surgery or medical treatment and later decide for themselves how they would like to identify – intersex, male, female or otherwise. Not all people with intersex conditions have genital differences and some do not know they are intersex until their body does not develop as expected at puberty, or when they want to have children.
Long term outlook
Unless they have a related medical condition, babies born with intersex conditions are natural and healthy. Their long-term medical outlook is no different than it is for other children. Some people with intersex conditions may require early surgery, if for example they cannot urinate, but many don’t.
Some trait variations result in medical issues such as problems making or regulating hormones, development issues during puberty and possibly increased cancer risk due to undeveloped tissue.
Early surgery to assign a sex may affect hormone levels later, and those born without various sex organs may need hormone replacement therapy.
Having intersex traits can also affect fertility. An intersex person with a uterus may be able to carry a pregnancy. Some intersex people have ovaries, a uterus, and a vagina, and may be able to become pregnant.
Our intersex research
The overall focus of our intersex research is to identify genes linked to intersex conditions, and the science behind underlying reproductive organ (gonad) formation in the developing embryo.
Our research has the potential to improve the understanding of what it is to be intersex, establish possible genetic links and causes, and improve diagnosis and clinical management of related health outcomes such as cancer risk, infertility, and gender dysphoria.
Improving genetic diagnosis of intersex conditions
Atypical male or female development in the womb leads to intersex conditions in about one per cent of babies. The quality of life of people who are intersex and their families can be affected by the condition’s cause, uncertainty about care choices, and chronic stress associated with stigma and lifelong clinical care.
Diagnosis is difficult, so this innovative study aims to uncover genetic causes by DNA sequencing, mapping the entire genome, and validating the genetic variations discovered in gonadal cell models. The long-term goal is to improve clinical care as part of a multidisciplinary collaboration with the Monash Children’s Hospital and Royal Children’s Hospital across individual.
Lead Researcher | Professor Vincent Harley
Modelling the genetic causes of intersex conditions
Our study has shown that key proteins SOX9, ATRX and FGF9 are needed to develop as a male. As a result, we are taking these variations identified in human patients and testing their effects in preclinical models. We are looking at how these genes/proteins express themselves and providing the information to clinicians to assist in their management of patients with intersex related conditions.
The team’s study has shown that key proteins SOX9, ATRX and FGF9 are needed to develop as male. They are now looking at how these proteins express themselves in preclinical models and using this knowledge to support clinicians in helping patients intersex related conditions.
Team | Professor Vincent Harley, Dr Stefan Bagheri-Fam
Genetics of gender incongruence
Gender identity is a person’s inner sense of their own gender. This may or may not correspond to the gender assigned at birth, typically due to biological characteristics. Gender incongruence (GI) occurs when an individual’s experienced gender and assigned sex don’t match.
Recent studies comparing the brains and DNA of people who are transgender (GI) and cisgender (identifying as your biological sex) suggest that GI may have a biological basis.
In collaboration with the , the team aim to further explore this possibility by comparing the DNA of transgender and cisgender individuals to see whether certain genetic factors are more common in transgender individuals. GI is common among intersex individuals and understanding it will help guide care.
Lead Researcher | Professor Vincent Harley
Intersex condition collaborators
Support for people with intersex conditions
Hudson Institute scientists cannot provide medical advice.
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