"We propose replacing the gender binary in elite sport with a more nuanced approach – an algorithm to be applied to all elite athletes (cisgender and transgender) that accounts for a range of physiological factors (including, but not limited to, testosterone levels), and gender identity.  In addition to providing fairness to elite ciswomen athletes, an algorithm could also provide fairness to elite transmen athletes. Although not discussed in the paper, elite transmen athletes are highly likely to be physiologically disadvantaged in comparison to elite cismen athletes. Even if (via hormone therapy) a transman’s testosterone level reached that of an elite cismen athlete, some of his previous female physiology is unlikely to change (e.g. bone structure and lung size) meaning that, in this respect, they are disadvantaged in …

The first official international football match was between Scotland and England in 1872 http://is.gd/5JXLhV /v @bestofwikipedia