One more:
Prof Ashley Grossman FMedSci, Emeritus Professor of Endocrinology, University of Oxford, said:
“We don’t know the details of the two athletes in question so we can’t make assumptions about what sex or gender tests they have or haven’t passed or failed in the past or at present.
“Some journalists are asking questions about DSD, or differences in sexual development, so here are some comments on what that is – though again I don’t know whether the athletes in question have this or not.
“Differences in sexual development (DSD) are extremely rare but are probably underdiagnosed and more common than we think. DSD is a whole class of differences – it doesn’t just mean one thing – and DSD is not a diagnosis in itself.
“The process of sexual development and differentiation is long and complex. We have the karyotype (which set of chromosomes we have), which determines the gonads that form during development, which then typically make internal sexual organs and then external sexual organs. External sexual organs usually develop father during puberty due to a rise in sex hormones, both male and female sex hormones. In the majority of people these changes are ‘consonant’, which means they proceed along a fairly constant trajectory, or line, such that the biological and hormonal changes are typically male or female. It should be emphasized that this development says nothing about gender identity or sexual orientation.
“But things go differently in some people, sometimes due to a genetic change, and they can have a ‘difference in sexual development’. If someone is diagnosed with a DSD they may be offered surgery or hormone treatment. Some people aren’t diagnosed until adulthood, but in many cases changes are seen in the neonatal period or childhood leading to investigation. Pediatric endocrinologists in particular are trained to deal sensitively with such patients to optimize their sense of themselves and their lives.
“When it comes to elite sport, it is up to the IOC and other bodies to make decisions as to how these things are dealt with. There may be an argument for not giving all athletes a baseline XX/XY sex chromosome test but only when there is a query to then test individuals, because there are all sorts of possibilities why someone might have certain sex chromosomes and an appearance that might be different.
“Not all DSD lead to higher (or lower) levels of hormones like testosterone – this depends on the specific condition.
“Adult male levels of testosterone do have an advantage when it comes to strength – testosterone levels in men and women can overlap, but even in women with polycystic ovarian syndrome (who may have slightly higher levels of testosterone than the average woman) the overlap is usually small. So a female with testosterone levels in the adult male range would likely have a strength advantage over other females. If someone has gone through male puberty they would – on average – have a strength advantage in female power sports, even if they then have low testosterone levels.
“But it’s not necessarily the case that having XY chromosomes in DSD always means someone goes through male puberty. Some individuals who have DSD and XY chromosomes would be given female hormones. Simply having the chromosomes doesn’t always mean people would have the expected testosterone levels.
“Some types of DSD would likely lead to advantages in sport, but it’s impossible to generalise. There is one type of DSD previously called testicular feminisation, now better called ‘complete or partial androgen insensitivity’ – where such individuals have male chromosomes (XY) but they lack the testosterone receptor and appear female as they don’t go through typical male puberty, so physically they are female. There is another type of DSD called 5-alpha reductase deficiency – these individuals would also have XY chromosomes but they usually would go through male puberty so would usually have higher levels of testosterone (some previous athletes with this condition have been required to take hormones to lower their testosterone levels to be eligible to compete, but this is a complex area).
“These are just two examples of DSD – there are many more, and we don’t know whether the athletes in question have these or indeed any other DSD.
“These issues are important for bodies like the IOC to address, in consultation with experts, but they are not straightforward.”
