During the Cold War, women from Eastern Europe excelled in international sport. Rather than applauding the successes of these female athletes, many in the Cold-War-West responded with suspicion, contempt and derision. Armed with rumours and anecdotes, the International Association of Athletics Federation (IAAF) implemented sex testing in 1966, and the International Olympic Committee (IOC) followed suit two years later. Despite the introduction of a compulsory sex/gender control, many continued to lament the muscular physiques of the Cold-War-Eastern victors. The known and suspected sex test ‘failures’ from North Korea, the Philippines, Poland, the Soviet Union and Spain served to exacerbate the fears of gender fraudulence. As global dynamics shifted, however, so, too, did the anxieties in sport. When women from the People's Republic of China dominated the international sports scene in the 1990s, many in the geographic-West again doubted the authenticity of the achievements and called for a return to gender verification. A decade later, the international plights of Indian athlete Santhi Soundarajan and South African runner Caster Semenya convinced the IAAF and the IOC that such a reestablishment was necessary. Using the ‘colonial/modern gender system’ framework, this article explores the political and racialised sex/gender concerns medical professionals and sport authorities possessed, which led to the establishment, abandonment and reintroduction of sex testing/gender verification in elite sport. Through these three phases of sex testing/gender verification, the IAAF and the IOC reaffirmed a binary notion of sex and privileged white, Western gender norms.