The XX male and XY female controversy in Sport and the Olympic Games
This photo taken in about 1990 is of me at the PALS picnic – with some of the babies, girls and boys, born in the PALS pregnancy and Lifestyle Study. These babies each had their chromosomes tested and were all either 46,XY (boy) or 46,XX (girl) as expected – unlike the individuals in Olympic controversies.
Hearing reports of gender-determination controversy at the Olympic games inspired me to look at the history of chromosomes and gender and my role in these studies.
When I was directing genetics laboratories in the 1970’s to 2000’s, we were quite often asked to determine a person’s gender (sex) by examining the chromosomes. In one case we found that a ‘man’ who was a true hermaphrodite i.e. half male and half female but this was exceptional! It was far more common to find that an apparently biological woman was genetically a 46,XY male, or that an apparently normal male had 46,XX (typically) female chromosomes.
In general, 46,XX males (often called XX male syndrome or De la Chapelle syndrome) exhibit male physical characteristics despite having two X chromosomes. This ‘syndrome’ is primarily due to the person having a normal copy of the SRY gene (the male sex-determining gene) that has been transferred (translocated) to one of the X chromosomes. So, although the individual has no recognisable Y chromosome, they have the critical ‘SRY’ = male-determining gene that is usually found on the Y chromosome.
46,XX males are usually infertile but they typically have male external genitalia, male secondary sexual characteristics and male hormonal profiles. They are often first detected through infertility testing as they often appear to be physically normal males, although with small testes. The diagnosis of a 46,XX male involves chromosomal and genetic testing, and management may include hormonal therapy and psychological support. In some families, it is an inherited condition.
XX males are usually only of interest to highly competitive sport when there is surgical intervention to create female external genitals, or the individual has been raised as a female. However, ambiguity of the genitalia occurs in about 15% of XX males and doctors might decide that it is easier to raise the child as a female and modify any genital ambiguity surgically.
Gender role and gender identity are usually reported as male unless the genitalia have developed within ‘female limits’ and it is appropriate to raise the child as female. It seems that the current Olympic controversy probably refers to just such cases. Yes, the chromosomes are female, but the SRY gene is also present and hence gives the individuals great advantage in muscle development and physiological response to testosterone.
XY females
In contrast, XY females, have been of considerable interest in sport and it was generally thought that they would always have a competitive advantage over normal XX females. However, XY females occur because of a condition called ‘Complete Androgen Insensitivity Syndrome (CAIS)’ and they are unable physiologically to respond to androgens! This condition is relatively rare. Estimates suggest that CAIS occurs in approximately 1 in 20,000 to 1 in 50,000 live births but so-called Partial Androgen Insensitivity Syndrome (PAIS) is estimated to be around 1 in 130,000 to 1 in 200,000 live births.
Because of ‘insensitivity to androgens’, it is very unlikely that being an XY female would confer any advantage in sports performance. With the complete gene mutation, the person’s body cannot respond to testosterone at all!
How does CAIS occur?
Genetic Mutations: CAIS is caused by mutations (changes/mistakes) in the androgen receptor (AR) gene located on the X chromosome. The prevalence of these mutations influences the incidence rates. The apparent incidence of the condition is strongly influenced by diagnosis and reporting so unless it is detected in some type of ‘fertility testing’ setting, it might well go undetected.
Understanding CAIS: Individuals with CAIS have a typically male XY karyotype but they develop female external genitalia and secondary sexual characteristics because their bodies cannot respond to androgens like testosterone.
CAIS individuals usually present at birth with normal female external genitalia. They typically lack a uterus and ovaries but have undescended testes, which may be located in the abdomen or inguinal region. Hernias caused by the testes are usually the reason that the condition is detected. Individuals with CAIS usually have normal breast development during puberty but do not menstruate due to the absence of a uterus.
Diagnosis and Management
CAIS is often diagnosed during infancy or childhood when atypical genitalia are noted, or later when menstruation does not occur at puberty. It often requires Estrogen replacement after puberty if the testes are removed. Counselling and support are crucial for dealing with issues related to gender identity and the psychological impact of the condition.
If the testes are undescended,surgical removal of the is often recommended to prevent the risk of testicular cancer.
Testosterone: Individuals with CAIS have normal or elevated levels of testosterone for males because they have testes, which produce this hormone. However, their bodies cannot respond to it due to defective androgen receptors. Estrogen: Some of the testosterone produced by the testes is converted into estrogen through a process called aromatization. Therefore, individuals with CAIS have higher levels of estrogen than typical males, but generally lower than typical females.
Related Conditions
Whilst controversy in sport is less likely to arise from full expression of CAIS, it is much more likely in what is labelled as Partial Androgen Insensitivity Syndrome (PAIS). Here we find individuals who have partial responsiveness to androgens, leading to a range of genital phenotypes from predominantly female to predominantly male. Generally, those with Mild Androgen Insensitivity Syndrome (MAIS) have mild symptoms and typically male external genitalia but may experience infertility or reduced virilization.
History of testing for 46,XY females and 46,XX males in Olympic Programs
Whilst we now understand that being a 46,XY female does not confer CAIS individuals with any advantage, we used to think it did and so this was undertaken from the 1960’s.
Early Gender Verification Tests
1960s – Physical Inspections: Gender verification in the Olympics began in the 1960s, initially through invasive physical examinations, known as “nude parades,” where female athletes had to undergo inspection by a panel of doctors.
In 1968 – the Chromatin (Barr Body) Test was introduced as this was a relatively inexpensive way of testing blood. Put simply, a normal female had a ‘Barr body’ in each of her cells due to the inactivation of her second X chromosome. Males had no such ‘body’.: The International Olympic Committee (IOC) introduced the Barr body test at the 1968 Winter Olympics in Grenoble and it was performed on a buccal smear (cheek scraping) to look for the presence of Barr bodies.
In 1992 – SRY Gene Test: The chromatin test was replaced by the SRY gene test in the early 1990s. The SRY gene is located on the Y chromosome and is responsible for male sex determination. This test was aimed at identifying the presence of the Y chromosome, thus identifying individuals with an XY chromosome pattern or (as above) people with an XX chromosome profile who were carrying the male determining SRY gene.
Ethical and Scientific Concerns
From the late 1990s there has been a Shift in Policy: Due to the growing understanding of intersex conditions and the recognition of the ethical and psychological harm caused by gender verification tests, the IOC and other sports organizations faced increasing criticism. Many athletes and advocates argued that such tests were invasive, discriminatory, and scientifically flawed. So we move ahead to more recent and current policies.
In 2000, we saw Suspension of Routine Gender Testing: In 2000, the IOC officially suspended mandatory gender verification testing for female athletes. It was decided that testing would only be conducted on a case-by-case basis in cases of suspected fraud.
In 2011 the IOC and the International Association of Athletics Federations (IAAF, now World Athletics) then introduced regulations concerning hyperandrogenism, which set limits on the levels of testosterone allowed in female athletes. Athletes with naturally high testosterone levels (typically found in some intersex conditions, including CAIS), and XX males were required to undergo medical evaluations and, in some cases, treatment to lower their testosterone levels to be eligible to compete.
From 2019, we now see the DSD Regulations: World Athletics has further implemented new regulations specifically for athletes with Differences of Sex Development (DSDs). These rules have targeted certain track events and require athletes with testosterone levels above a certain threshold to take measures to reduce their testosterone levels if they wish to compete in the female category.
Not surprisingly, the policies regarding hyperandrogenism and DSDs have been highly controversial and have faced legal challenges from affected athletes. Critics argue that these regulations are discriminatory and violate athletes’ rights to privacy and ‘bodily autonomy’. Prominent cases include those of South African runner Caster Semenya and Indian sprinter Dutee Chand, who have challenged these regulations in court.
The history of testing for 46,XX males (presenting as females) in the Olympics reflects a broader struggle to balance fair competition with respect for athletes’ rights and well-being. As scientific understanding and societal attitudes continue to evolve, the policies and practices regarding gender verification and DSDs in sports are likely to undergo further changes.
Can this argument ever be resolved?
As we all know there is an almost infinite number of possible variations in human form and development and many of these confer advantage and/or disadvantage in competitive sport. Even my own case of having three close relatives who were international champions gives me some potential advantage. So, as there is no bias against those who have great athletic genes (I’m not including myself here), should there be bias against those who naturally develop bigger muscles or higher hormone levels?
If we examine intersex per se, we find that there are at least seven different intersex types but many other defined individual genes or mosaic conditions (where there is more than one cell lineage in an individual). And these are the ones that are studied. Who knows what could be hidden?
Perhaps we need some ‘open’ and ‘closed’ competition categories? Right now, this is still contraversial.