At first glance, Fallon Fox appears to be just another female mixed martial arts prospect. At 5-foot-7 and 145 pounds, the slender featherweight is dwarfed by her male trainers.
But Fox is not your typical female MMA fighter. She is transsexual -- born a male.
Fox, 37, underwent sex-reassignment surgery in 2006. But she did not publicly reveal her gender status until March 4, following a first-round knockout of Ericka Newsome at Championship Fighting Alliance 10 in Coral Gables, Fla.
In the same venue Friday night, Fox (2-0) faces Allanna Jones (2-1) in the co-main event of CFA 11. But since her revelation, Fox has been the subject of a heated MMA debate: Should a transgender female be allowed to compete against women?
Fox's detractors are uncomfortable seeing her punch, kick, choke or disfigure the limb of other female competitors. UFC heavyweight Matt Mitrione was fined and suspended for three weeks after he made offensive comments about Fox. While not condoning Mitrione's conduct, UFC president Dana White agreed with Mitrione that a transgender fighter such as Fox should not be allowed to fight other women.
A number of female mixed martial artists have expressed reservations about fighting her.
"I wouldn't do it," UFC bantamweight contender Miesha Tate told ESPN.com in March. "If there was solid research that [proved] she's 100 percent like a female, then I might consider it.
"I have nothing against transgender people. You should live your life however you want. It's about fighter safety. I wouldn't feel comfortable getting in with someone who is a woman but developed as a man. I just don't think it would be safe."
UFC bantamweight champion Ronda Rousey told the New York Post she would fight Fox at the UFC's request, although she believes Fox has a physical advantage against female fighters.
Fox, however, does have supporters among the fighting community.
"I understand she fights in a regional organization right now, but if she makes it to the UFC, and fights in the 135-pound female bantamweight division, I'd be happy to fight her," said UFC bantamweight contender Liz Carmouche, who is lesbian. "But that's all hypothetical -- what I can say for sure is that I understand what it is to be a [lesbian, gay, bisexual or transgender] athlete in the spotlight like she finds herself in right now and that I'm glad she's got the support of the LGBT community behind her."
Fox takes comfort in knowing she isn't the first athlete to be at the forefront of an equal rights struggle, and she isn't likely to be the last. Yet despite her resolve, Fox has gone through difficult periods, moments when she feels burdened by her struggle and needs strength to press on.
During those times Fox recalls the indignities baseball legend Jackie Robinson endured and overcame and finds the inspiration to continue fighting.
"I see similarities between Jackie Robinson and myself," said Fox, who refers to herself as transsexual, not transgender. "The reason people were so worked up about him … is because he was the first African-American [major league] baseball player. He wasn't understood, just like I'm not understood.
"I recently saw the movie '42.' I especially noticed the part when the announcers said [Robinson] had an unfair advantage because the shape of his bones was different. It's some of the same things that are being said about me."
Fox said "ignorance" is a major factor fueling the backlash against her and believes education will help alleviate some of the hostility. And the education process has already begun in the MMA community, at least legislatively.
In the summer of 2012, at an Association of Boxing Commissions convention in Florida, Dr. Sheryl Wulkan, who is the organization's medical committee chairperson, drafted guidelines for the participation of transgender fighters in MMA and boxing. Wulkan's action not only served to make ABC members aware of transgender participation in combat sports; it also helped educate them about the need to address potential safety matters that might arise.
The ABC, which is made up of members from state and tribal commissions throughout the U.S. and Canada, sets policy guidelines for boxing and MMA commissions. The association adopted the recommendations put forth by Wulkan, who is the lead MMA physician for the New Jersey State Athletic Control Board.
"We've tried to educate our [ABC] members because this is new," said ABC president Tim Lueckenhoff who also serves as the Missouri Office of Athletics executive director. "Dr. Wulkan brought this to the ABC last summer, to its convention, but before that time I hadn't really thought about it a whole lot.
"Luckily, [Wulkan] had some forethought that this issue might be coming because it prepared us for what has happened this year. Obviously, I will have our doctors take a look at [Fox] if she comes here. They will have to be the experts when she comes here."
ABC's guidelines were used by the Florida State Boxing Commission and met by Fox, clearing the way for her to fight Friday night. The Championship Fighting Alliance conducts most, if not all, of its shows in Florida. But should the promotion opt to do a show in New Jersey, for example, and wanted to feature Fox on the card, she would have to meet the same guidelines.
"If [Fox] meets the requirements, she gets licensed. If she doesn't, she doesn't," NJSACB attorney Nick Lembo said. "It is our responsibility as a commission to make sure that fighters are evenly matched from a medical and skill standpoint. The fights have to be fair."
Other state commissions are also addressing the transgender fighter issue, but most are not as far along in the process as New Jersey, Florida and Missouri, which also rely on the ABC guidelines. Most have yet to confront this issue directly.
Nevada Athletic Commission executive director Keith Kizer said Fox would likely have to overcome many more hurdles than those put in place by the ABC. Kizer hasn't ruled out the possibility of Fox competing in Nevada one day, but he hasn't made guarantees that she will.
"The short answer is, 'I don't know,'" Kizer said. "We've never had this issue. Here is my thinking on it, but it wouldn't be my call, of course: We'd start with the ABC guidelines; we'd start with the Olympic Committee guidelines. That would be the bare minimum, I guess.
"[Fox] would have to comply with those guidelines at the very least. Then the question for this commission, initially through our medical advisory panel and then the full commission is, what other safeguards should be put in place? What other requirements should be made of the fighter?
"And I just don't know what those would be. This is not someone competing in [track and field]; this is somebody competing in a combat sport. So you want to make sure that they are safe as well as their opponent."
The possibility of competing in states other than Florida is important to the continued development of Fox's pro fighting career. She hopes to one day compete against some of the world's best MMA fighters. Claiming the CFA featherweight tournament title would be a good start; her fight with Jones is a semifinal bout.
"It will mean that a lot of my hard work has paid off," Fox said. "Winning a pro tournament is another step toward getting fights against higher-ranked opponents."
To accomplish her goal of facing higher-rated opponents, Fox will surely have to receive a license to compete in Nevada, New Jersey, California and Missouri, where top women's MMA promotion Invicta FC conducts its business.
With only a few pro fights under her belt, Fox has very little room for error. She must continue winning and improving as a fighter before Invicta FC president Shannon Knapp might give her a call.
It's too soon to determine whether Fox will develop into a fighter who catches Knapp's eye. The door to Invicta FC isn't closed to Fox, but it's not yet open, either.
"I've only seen one fight that she has been in and that's her last fight," Knapp said. "It was a quick fight, a quick finish. It's hard to gauge where a fighter is [skill-wise] from one fight that ends so quickly, and you haven't seen her other fights as she comes up the ranks.
"It was an impressive win in that fight, but to judge where she is at this point in time would be really hard for me."
In her most recent fight on March 2, Fox used a knee to the chin to knock out Newsome in 39 seconds. Fox has demonstrated solid striking in her two professional fights, but she quickly dispels any notion of being a one-dimensional fighter.
"I'm very good at submissions from the ground," said Fox, who won her lone amateur fight with a first-round armbar. "I have good takedowns and good striking, so I'm pretty well-rounded."
A win Friday night could move her one step closer to proving she can compete against high-level competition. But piling up early knockouts and submissions could hinder Fox's chances of competing in a higher-profile promotion. Despite ABC's guidelines, for some, she doesn't pass the eye test in the cage.
"She looks to have a physical advantage," said Mike Constantino, a New Jersey-based MMA trainer. "She looks bigger, stronger and faster than her opponents.
More than anything, Fox wants to be treated fairly, and that's exactly how Knapp is approaching any future decision about her. But the issue of fairness isn't limited to Fox, and she knows it.
If Fox continues to improve as a fighter and one day becomes a free agent, talks with Invicta FC might arise. At that time, Knapp expects she must reach a decision that is fair to Fox and the other female fighters on the promotion's roster.
While the issue is not on Knapp's to-do list, she considers it a priority to learn more about transgender/transsexual female fighters competing in MMA.
"[Fox] is fighting with another promotion," Knapp said. "I've always felt it was very unprofessional and disrespectful to say that I want that athlete or that I aspire to have that athlete or anything like that.
"This is very uncharted territory in the sports world, and I don't know if I've had the opportunity or the time to really sit down and to be educated about this. We're committed to building a sports franchise and to elevate the female athletes in this sport.
"I have to be more educated about this, and when the time comes I will be in a better position to speak from an educated position about it."
Whatever decision Knapp reaches, one fighter unlikely to object to Fox joining the Invicta FC family is featherweight titleholder Cristiane "Cyborg" Justino.
"I think you're born a girl, you're a girl; you're born a guy, you're a guy," Justino told ESPN in April. "But I don't choose opponents. The commission needs to check and make sure she doesn't have testosterone. I'm not going to judge other people. If the commission says she can fight, why not?"
Having Justino's support doesn't hurt Fox's chances of competing against higher-rated fighters sometime in the future. But it still doesn't guarantee she will ever get that opportunity.
Fox can't control the opinions of others, whether informed or not. What she can do is continue fighting, inside and outside the cage, and hope things improve for her and other transsexuals who might consider becoming mixed martial artists.
But fighting for equality and understanding aren't all that matter in Fox's life. In addition to fighting, Fox focuses most of her attention on being a single parent and enjoying herself.
"I've been raising my daughter, who just turned 17, for a few years now," said Fox, who is the biological parent of her daughter.
"I like watching women's MMA; that's the only sport I watch. I like playing video games in my spare time. I like [science fiction] things a lot -- 'Star Trek,' the 'X-Men.' I like Dave Chappelle; I wish he was still on TV."
Fox also would like to see the day when she does not have to answer questions about being transsexual.
"I do hope that day comes," Fox said. "If it does, that would be awesome. But if it doesn't, I will continue doing what I do."