We support gender equality and freedoms in cases in which ‘like equals like’. Such inclusion is central to a progressive society. However, inclusion could potentially conflict with fairness in cases concerning transgendered athletes in elite sport. Accepted science regarding male and female physiology suggests that transwomen have an advantage over their cisgendered counterparts. This advantage stems from relatively high testosterone levels and prior male physiology of transwomen. Conversely, transmen who wish to compete in the men's division may be disadvantaged in comparison with cismen. Hence, while inclusion supports transwomen and transmen competing in the division that matches their gender identity, this may not satisfy the principle of fairness. We reason that transwomen and cismen are not only advantaged, but unfairly advantaged, and propose that the gender binary in elite sport should be replaced with a nuanced algorithm that accounts for both physiological and social parameters. As the algorithm would be applied to all athletes, it would be both inclusive and fair.