Sex verification via physical inspection, by the International Amateur Athletic Federation (IAAF) in 1966 and 1967
There are some reports that female athletes at IOC (International Olympic Committee) events in the 1960s were required to do a "nude parade" in front of medical experts to try to verify if their biology was feminine enough. This page lists the available documentation.
[T]he lab is a relic of an earlier Olympic era, when every female athlete was required to submit to a sex-verification test. The tests emerged in the 1960s, when the Soviet Union and other Communist countries were suspected of entering men in women's events to gain an edge. At first, women were asked to parade nude before a panel of doctors to verify their sex. At the 1968 Olympics in Mexico City, officials switched to a chromosomal test.
[I]n 1966 international sports officials decided they couldn’t trust individual nations to certify femininity, and instead implemented a mandatory genital check of every woman competing at international games. In some cases, this involved what came to be called the 'nude parade,' as each woman appeared, underpants down, before a panel of doctors; in others, it involved women’s lying on their backs and pulling their knees to their chest for closer inspection. ... Amid complaints about the genital checks, the I.A.A.F. and the I.O.C. introduced a new “gender verification” strategy in the late ’60s: a chromosome test.
Ian Ritchie notes: "In 1966, the International Amateur Athletics Federation (IAAF) required athletes to undergo a physical inspection by three female gynecologists at the European Championships in Track and Field [Budapest, Hungary]... In the same year, a pelvic examination was required for athletes entered in the Commonwealth Games in [Kingston] Jamaica. At the European Cup Track and Field events in 1967, the IAAF added chromosome testing to the visual inspection (2003, p. 87)."
Simpson, et al. (2000) also report that "physical inspection was made of disrobed female athletes" at the 1966 European Track and Field Championships and the 1967 Pan American Games in Winnipeg [Canada] (see also Puffer, 1996); and that "gynecologic examinations were performed" at the 1966 Commonwealth Games (p. 1568).
Cassandra Wells, a doctoral candidate at the University of British Columbia who has been researching this issue in the IOC archives in Lausanne, is fairly sure that: "...the only hard evidence for the naked parades came from IAAF-sponsored events like the World Championships and the Commonwealth Games. [I]n the IOC archives [I] only found reference to lab-based testing. That said, the IOC was certainly 'in' on the IAAF plans and was watching them carefully. There was overlap in their medical advisors (there still is) and femininity testing was regularly on the agenda of IOC meetings of that time (personal communication, 17 May, 2013)".
Bruce Kidd reports that several scholarly papers on sex testing were presented at the annual meeting of the North American Society for Sport History (Halifax, NS, CANADA, 24-27 May, 2013): "[t]he consensus is that the visual parades were limited to IAAF events in 1966 and 1967 before the chromosome test was introduced in late 1967" (personal communication, 26 May, 2013)
References:
Puffer, J. (1996). Gender verification: A concept whose time has come and passed? British Journal of Sports Medicine, 30(4): 278.
Ritchie, I. (2003). Sex tested, gender verified: Controlling female sexuality in the age of containment. Sport History Review, 34: 80-98.
Simpson, J., A. Ljungqvist, M. Ferguson-Smith, A. de la Chapelle, L. Elsas II, A. Ehrhardt, E. Ferris & A. Carlson (2000). Gender verification at the Olympics. Journal of the American Medical Association. 284(12): 1568-9.
Although intermittent "sex tests" had occurred at earlier Games, starting in 1966, officials at IAAF events began requiring women to submit to physical inspections before competitions, assuming that this would deter potential female impostors (Wrynn, 2004). Since this proved demeaning, the IOC introduced the buccal smear test as a screening method in 1968. This test served as a proxy indicator of XX (classified as female) or XY (classified as male) chromosomes and had the advantage of being relatively non-invasive, but it neglected the array of developmental possibilities where chromosomal, gonadal, hormonal, anatomic, and psychosocial sex may be discordant.
References — Wrynn, A. (2004). The human factor: Science, medicine and the International Olympic Committee, 1900–70. Sport in Society, 7, 211–231. doi:10.1080/1461098042000222270.
Pieper, Lindsay Parks (2014). "Sex Testing and the Maintenance of Western Femininity in International Sport". The International Journal of the History of Sport. 31 (13): 1557–1576. doi:10.1080/09523367.2014.927184. S2CID 144448974.
Swayed by public opinion and medical validation, the IAAF introduced a visual examination; in the 1966 European Athletics Championships, three female doctors inspected the genitals of the 243 women participants.42 Physical inspections continued in the 1966 Asian Games. Notably, Philippine star sprinter Mona Sulaiman – who had, in record-setting times, won the 100-metre and 200-metre races in the previous Asian Games – refused to undergo the examination. She later explained that a severe case of the flu had persuaded her to forego the procedure.43 Unfortunately, officials and the public alike dismissed her illness as a facade and maliciously expressed misgivings. When solicited for a comment regarding Sulaiman’s refusal, the Philippine team physician Antonio Vergara responded that ‘of course, I have my doubts’, inferring that athletic successes stemmed solely from non-feminine characteristics. A teammate similarly voiced scepticism, noting that ‘she acts like a girl, but she talks like a man’.44 More overtly hostile, Sports Illustrated writer Marvin Zim chided that ‘still left unanswered is the question of whether Mona is a Filipino or Filipina’.45 Along with a disregard for human dignity, this comment also highlights the racial undertones of sex/gender testing. Sulaiman returned home under a cloud of suspicion, her athletic career desecrated. Interestingly, she fended off the resultant local incertitude by boldly daring those who challenged her identity to allow their husbands to join her for an overnight visit.46 This line of reasoning insinuated that femininity could be verified through a demonstration of heterosexuality. Public condemnations of sex test failures continued the following year, as did novel attempts to scientifically pinpoint biological difference. The IAAF instituted a chromatin test for the 1967 European Cup Track and Field Event, thereby replacing physical inspections.
42. Ferguson-Smith and Ferris, “Gender Verification in Sport,” 17.