To the left there is Parinya Charoenphol. She was a male kickboxer until deciding to go through with a sex-change operation. To the right is Asanee Suwan, who will play her pre-change in a movie to be filmed about her life.
This is interesting to me because the aggression involved in such a sport seems to be very male in origin, very testosterone-based. Physical contact sports always involve a lot of really male stuff - getting deep within your male attitude, finding the inner animal, etc. Eating raw meat, grunting, that sort of thing.
Like the recent South Park where the first girl in the kids' class grows boobs, and the boys turn into aggressive ape-like creatures when they compete for her attention. Oh god that was hilarious.