When Renee Richards won the right to compete as a woman in tennis’ U.S. Open in 1977, she opened the door to decades of transgender women following in her footsteps. Yet in the last few years what had seemed to be a trickle has become a steady stream, with transgender girls and women competing in high school, college, and professional sports.

As we approach the 2020 Summer Olympics, there is some indication that one, or even a couple, of transgender athletes may earn spots on their national Olympic teams.

The debate that has been ignited about the inclusion of trans women in women’s sports has exploded, with people across the sports world weighing in on issues of science, medicine, competition and fairness.

In this series of articles, Outsports co-founder Cyd Zeigler explores various aspects of the debate, with the aim of finding recommendations for policies and attitudes that can help guide a sports world whose core values of participation and inclusion are balanced with the drive to win.