I've already stated my opinion on the matter.
I don't support Fallon Fox fighting women.
But I don't think he (I refuse to call Fallon a "she"), should be subject to ridicule for being transgendered. In fact, I find several comments that I've read about Fallon to be downright disgusting. He's a sentient human being who is allowed to do whatever he pleases with his body. Just because he feels that he is a woman does not mean that he isn't a good person or isn't an individual of high character. That's what people should be judged on, not what is inbetween their legs.
I would now like to present an alternative:
What if Kobe Bryant became transgendered? Do you think he should be allowed to play in the WNBA?
What about Bryce Harper playing in a pro softball league?
If there was a female NFL counterpart, should a trangendered Clay Matthews be allowed to play against women?
Just interesting to think about.