I'm glad Steph Daniels from Bloody Elbow is looking into all of this, uncovering for herself and MMA fans what we in the LGBT community have known for years:

Steph Daniels: Does Fallon carry a significant advantage in mixed martial arts competition, due to being biologically born a male?

Dr. Marci Bowers: Most measures of physical strength minimize, muscle mass decreases, bone density decreases, and they become fairly comparable to women in their musculature. After as much time as has passed in her case, if tested, she would probably end up in the same muscle mass category as her biologically born female counterpart.

Dr. Sherman Leis: She's been doing that (hormone therapy) for so many years, that she probably does not have a significant advantage, if any at all. Especially because she wasn't a big man when she lived as a male. She's 5'7 and slight of build, and basically the size of an average female. Factor in that she's been on hormones for so long, and has had the surgery, she more than likely has the muscle mass, bone density and strength of most females.

Great job, Steph! Keep asking questions!