In competitive sports, society has for a long time distinguished between gender when deciding how to group competitors. For a long time, a penis and testes have defined a male and male features. I understand hormones largely play a role in our physique and emotional nature. And the testes are a primary source of testosterone. However, today, we have, among other things, steroids and hormone therapy which can effectively cause gender change with regards to physique and competitive outlook. When I was younger I wrestled. We were classified by weight to make competition fair. I would imagine each sport has its own unique criteria. If we take gender out of the competition equation, for the sport for which you are most familiar, what new variables must we use to keep competition in that sport fair?