Natural Selection for Genetic Variants in Sport: The Role of Y Chromosome Genes in Elite Female Athletes with 46,XY DSD

Abstract

At present, it is widely assumed that hyperandrogenism in female athletes confers an unfair competitive advantage. This view is perpetuated in current regulations governing eligibility of female athletes with hyperandrogenism to compete, which identify testosterone levels in the male range as the critical factor. Detailed evidence is presented here for the first time that genes for stature (and possibly other genes) on the Y chromosome are responsible for the increased frequency of 46,XY disorder of sex development (46,XY DSD) among elite female athletes identified by eligibility tests. In many cases, androgens are non-functional or, alternatively, absent and therefore testosterone cannot be responsible for their athletic success. Genetic variation has a major role in the selection of individuals for training and success in competition; however, this variation is not grounds for determining who should compete in athletic events. There is no convincing evidence to support the view that hyperandrogenism is associated with performance advantage in female athletes. Current time-consuming regulations may lead to the unwelcome resurgence of innuendo in the media and coercion of female athletes into accepting gonadectomy and other treatments to which they might otherwise not have been subjected. These regulations should be withdrawn on the grounds that they are not supported scientifically, are discriminatory towards women and place some female athletes at risk of unnecessary and potentially harmful investigations. Improved understanding about genetic factors that lead to selection in sport should offer reassurance that women with hyperandrogenism possess no physical attribute relevant to athletic performance that is neither attainable, nor present in other women. Key PointsY genes for stature (and possibly other Y genes) are responsible for the increased frequency of 46,XY DSD among elite female athletes identified by eligibility tests.Hyperandrogenism is not associated with performance advantage in female athletes.Governing bodies in sport should withdraw their regulations on hyperandrogenism.

Hyperandrogenism controversy in elite women’s sport: an examination and critique of recent evidence

“…The IAAF acknowledged this fact in their previous study to determine whether unusually high levels of testosterone in women provide a competitive advantage, which used the same data from the 2011 World Athletic Championships in Daegu 6. They stated that they were unable to exclude other variables that ‘…in some unknown way may bring an advantage to female athletes’ (see also Ferguson-Smith and Bavington7). …”

Determination and regulation of body composition in elite athletes

“…The women with severe AIS are physically and culturally normal women, often tall and slim and ‘athletic’. They are over-represented in athletic communities,11 their height is on average that of men and they have little body fat.…”

“…The undoubted excess of women with XY disorders of sex development (DSD) especially AIS in elite athletics, that the IOC and IAAF attribute to performance enhancing effects of the high serum testosterone, is almost certainly due to other factors determining body composition and sporting ability carried on the Y-chromosome 11. Ferguson-Smith has in this paper and elsewhere proposed that the apparent sporting advantage in women with AIS comes from the facts that they are tall and have a high LBM and low amount of body fat.…”

Bilateral Sertoli-Leydig cell tumor in a patient with complete androgen insensitivity syndrome: a case report and brief review of the literature

“…The genetic component in the case of sex segregation in sports seems largely provided by the Y chromosome. Tallness, whether determined by genes on the Y or any chromosome, offers an example of an acceptable variable that contributes to athletic success in elite female athletes, including those with 46 XY (Ferguson-Smith & Bavington, 2014).…”