  A more fundamental challenge has been levelled at the very institution of sex segregation in sport. It has been proposed that the organisation of sport should be indifferent to an athlete’s sex, so men and women should compete with and against each other. On this view, rather than retaining sex segregation, which involves discrimination against women as well as complex questions concerning the proper categorization of intersex, trans, and non-gendered athletes, we should eliminate sex segregation altogether, and sport should either be open (not segregated at all) (Tamburrini, 2000a, ch. 6; Tännsjö, 2000) or segregated along dimensions other than sex such as weight, height, haemoglobin level, or testosterone level (Knox et al, 2019).