How should gender be defined in Olympic sports?

There were no women athletes in the first modern Olympic games. The next time around, in the 1900 Paris games, out of 997 athletes there were 22 women, who competed in just five acceptably ladylike sports: tennis, sailing, croquet, equestrianism and golf. Over a century later, the introduction of women’s boxing meant that the 2012 Olympics were the first to feature women competing in all sports. But that moment of parity has been followed almost immediately by a drastic challenge to the very definition of women’s sport, as the International Olympic Committee brought out new rules last November on the inclusion of trans athletes.

The change of rules has been followed by news that two unnamed British athletes who were born male are now in contention to compete as women in the 2016 Games in Rio. However, although 2016 could be the first Olympics with transgender athletes, it’s not the first time they’ve been permitted: the 2003 Stockholm Consensus on Sex Reassignment in Sport confirmed that trans athletes could participate, provided they had undergone sex reassignment surgery, had been receiving hormone therapy for a minimum of two years, and had legal recognition of their new gender.

The 2015 Consensus scotches one of those stipulations, and limits the other two: now, trans competitors no longer need to have genital surgery, and female-to-male transitioners can compete as men without restriction.