Transgender cyclist Rachel McKinnon continues to dominate women’s cycling. It has not been an easy ride. Last weekend at the Masters Track Cycling World Championships in Manchester, England, the 37-year-old Canadian first set a world record in qualifying for the 35-39 age category 200-meter sprint, then went on to defend her title in the finals. Her success, however, has been overshadowed by frustrated competitors. In an interview with Sky News, former cycling champion Victoria Hood said, “It is not complicated. The science is there and it says that it is unfair. The male body, which has been through male puberty,...