Sharron Davies, an English former competitive swimmer who represented Great Britain in the Olympics, discusses how she became embroiled in the debate over men participating in women’s sports in 2019 as she foresaw problems where the inclusion of these men “has the potential to ruin women’s sport.” Having followed the science for many years on this issue, Davies shares her experiences of having had to compete against East German swimmers who were given testosterone to outperform their competitors in what can only be described as a full-blown state-run doping programme. Reviewing the science while arguing for fairness in sports, Davies details how today mediocre male athletes can shift categories and outperform top female Olympians. This obviously poses an existential threat to women’s sports in addition to robbing women of titles, careers, economic remuneration, scholarships and many high profile opportunities which serve these athletes throughout the prime of their careers and beyond retirement.