Olympics and Women...
1900: Women first participated in the modern Olympic Games in Paris, France, where they competed in five sports: tennis, sailing, croquet, equestrianism, and golf. However, women were only allowed to compete in sports that were considered compatible with their femininity and fragility, and were excluded from track and field.
1928: Women were allowed to compete in athletics, gymnastics, and fencing, and women's track and field debuted at the Amsterdam Games.
1991: The International Olympic Committee (IOC) implemented a rule that any new sport seeking to join the Olympic program must have women's competitions.
Working on 1% improvements. Probably neither DNA, hormone level, or banned substance testing in 1900, so yeah, let's just go with femininity.
Give the IOC another 100 years, and it will straighten this all out to everyone's satisfaction.