Professional Sports Leagues
National Women's Hockey League
The National Women's Hockey League (NWHL) released a policy in December 2016, making it the first women's professional sports league to have a formal policy in place regarding the participation of transgender and non-binary athletes. The policy allows trans men not taking hormones to participate, and allows transgender women into the league following one year of cross hormone therapy.
DOWNLOAD: NWHL Transgender Athlete Policy
To our knowledge, no men's professional sports leagues have formal policies on the participation of transgender athletes.