New Eligibility Regulations for female athletes with “Differences of Sex Differentiation”

By Simon Franklin, Jonathan Ospina Betancurt @JonathanOspinaB and Dr Silvia Camporesi @silviacamporesi 

New Eligibility Regulations for female athletes with “Differences of Sex Differentiation” have been put forward by the International Association of Athletics Federations (IAAF) today (26 April 2018) (

The regulations say that athletes, including Semenya, will have to reduce and then maintain their testosterone levels to no greater than 5nmol/L by 1 November 2018 if they want to compete in events ranging from 400 metres to a mile.

These new regulations imposed by the IAAF and valid from today target specifically Caster Semenya and follow a logic that our article ( ), and original blog post ( ), specifically warned against. The ruling seems to be based on an interpretation of the evidence put forward in the study by Bermon et al ( that says that it is only in the middle distance events that hyper-androgenic female athletes have an advantage. We argue that this reasoning is entirely misguided.

Contrary to what IAAF claims, science is not its side.  Both our article ( and the article by Sonksen et al ( showed that the Bermon et al study on which IAAF is based is severely flawed.

One of our central points in the article was that in the presence of multiple hypothesis tests- those few events that show up as significant would be a result of pure chance. Thus, if IAAF continued to make policy on the basis of such statistical findings, they would likely have to change the events to which these regulations apply every time such that a study replicated with new data, and therefore the group of events would be likely to change every time. This would mean, regulations applying to events ranging from 400 metres to a mile today, and regulations applying to a completely different set of events another time. This, obviously, seems like a very arbitrary and selective way in which to apply regulations, and seems targeted towards Caster Semenya.

Further, even if the ruling had applied only to the 400m and 800m, and not the 1500 metres, such a selection of events would be entirely  arbitrary, as we argue in our BJSM article (, where we applied a correction procedure which controls the false positives discovery rate across the tests conducted in the Bermon paper. After performing such test, we found that the pattern of p-values found in the Bermon paper, across all women’s events is consistent with there being no advantage to high fT women, in any of the events. In other words: it is likely that the correlations presented in the paper occurred simply by chance. Therefore, we cautioned researchers, practitioners and regulators interpret the statistical results in Bermon and Garnier 2017 with extreme caution. Exactly the opposite of what IAAF have done.

They IAAF have cherry-picked a few events for which a statistically significant correlation was shown in the original Bermon/Garnier study, and applied restrictions on athletes only for those events. This constitutes a seriously wrong application of scientific findings- exactly the kind that we warned against.

Simon Franklin is a Postdoctoral Research Economist at the London School of Economics and received his PhD in Economics from the University of Oxford. His primary research interests include urban labour markets and housing policy, though he has a keen interest in elite athletic performance, and methodological questions related to statistical inference more generally. 

Jonathan Ospina Betancurt (@JonathanOspinaB) is a lecturer in Sport Science & Physical Activity at Universidad Isabel I, Spain. His most recent research examines Sex-differences in elite-performance and hyperandrogenic athletes. His fields of research are DSD and transgender athletes, ethics and values in sport. Is a JHSE Associate Editor.

Dr Silvia Camporesi (@silviacamporesi) is a lecturer in Bioethics & Society at King’s College London, where she directs the MSc in Bioethics & Society. Her latest book, “Bioethics Genetics and Sport”, co-authored with Mike McNamee, is forthcoming for Routledge in March 2018.


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