At the duathlon national championship, Chris Mosier became the first openly transgender athlete to qualify for Team USA in the gender with which he identifies. He describes his decision to transition and explains why he belongs on the starting line. (4:26)

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BY THE TIME Chris Mosier hit the ice machine in the Ramada Inn lobby at 8:30 a.m., he'd already run 20 miles, wending through the silent streets and wooded bike paths of Marquette, Michigan, and along the shoreline of Lake Superior.

As a recently qualified member of the U.S. national triathlon team -- his event is the sprint duathlon, a run-cycle-run race -- Mosier is training for his first world championship in Spain next June. Ice baths are part of the 35-year-old's regimen, so Mosier holds the clear, flimsy bag from his room's trash can under the machine, trying to collect enough to fill his tub in a few trips from the eighth floor.

Back in his room, Mosier takes off his running shirt, drapes his head and muscled shoulders with a hotel towel and winces as he steps into the ice bath. He sits down with a violent exhale and a shudder. "Oooh, it's pretty bad," he moans. He exhales again, closes his eyes and squeezes his hands.

Mosier is slight and spry, with a 1,000-watt smile. He instructs thousands of athletes online and coaches more than 100 in person. He appears, even out of their earshot, genuinely thrilled each time any of them hit their goals. "Pumped" is a word he frequently uses to describe his emotional state.

But up close, after a two-and-a-half-hour run on a bad night's sleep, Mosier looks a bit battle worn. His iced skin is salmon red and chapped; there's no fat on his body, no sign of indulgence, just gnarls of muscle. A long white scar snakes across his collarbone from when he got hit from behind while biking in 2013. And there are two purple and white scars on his chest from a surgery he had as part of the transition to physically becoming a man.

When room service arrives with eggs, pancakes, hash browns and orange juice, he lifts himself out of the bath. Two hours later, he's dressed in a royal blue tailored suit with a pin at the lapel showing the American flag, with the Olympic rings beneath. Mosier, the first known out transgender athlete to qualify for any U.S. national team, is trying to be a trailblazer in the way Jackie Robinson was a trailblazer: busting through rules that still seek to exclude people like him, winning the right to compete at his sport's highest level. He wants to be seen, to force the world to make a space that isn't there. But due to the muddled policies of the international sports world, it's not clear whether Mosier will get the chance. And the way his case is handled by athletic governing bodies could set a precedent that ripples through the sports world.

On this September morning, he's off to Northern Michigan University, his alma mater, invited to speak at a diversity event. It will be his first visit to campus since he graduated 12 years ago. Mosier's day job is as assistant director of residential life at Marymount Manhattan College, but he spends the rest of his waking hours on training, coaching and advocacy. He is executive director of a national LGBTQ student-athlete network, GO! Athletes, which advocates for and mentors LGBTQ athletes; the night before, he'd led a conference call with former NBA player Jason Collins from his hotel room. On his site, transathlete.com, Mosier compiles a list of sports organizations' policies for allowing transgender athletes to compete. He also consults on how to make organizations more trans inclusive.

Mosier's path has taken him many places -- he was invited to the White House in 2011 -- but he wasn't sure he'd ever come back to NMU. He lived in college as an androgynous and confused woman, and some of his memories of harassment and isolation are painful.

As he enters University Center, a 1960s-era brick building with beige cinder-block halls, he feels nauseated and light-headed from his run. He slams three glasses of lemonade and rests in an armchair before heading into the conference. Mosier is devoted to being out and to being an advocate, but he's at least a bit conflicted about all that comes with that. Private by nature, he takes umbrage at the wide range of questions that get thrown at trans people.

The conference room is set up with hundreds of chairs, but only about 30 people have gathered to hear the current speaker. It's hard to tell whether anyone will show up for Mosier's talk, but when the speaker concludes, more than 100 students and teachers have poured in. Mosier's whole energy changes when he takes to the podium. His talk is a funny, heartfelt discussion of his transition. He tells the audience that he used to perform as NMU's Wildcat Willie mascot. When people photographed Willie, Mosier always smiled inside the yellow furry head. "I smiled biggest for photos when no one could see me," he says. "I spent a lot of time here trying to make myself invisible."

After Mosier's speech, a line forms. "I'm Kayleh and this is Nikki, and we just want to say you are awesome. Can we take a selfie with you?"

An administrator quietly tells Mosier, "It's good you were here, good to see you. We are very proud of you." Mosier gently chides him, "You guys need to get some gender-blind dorms."

Alex Clark, a 24-year-old English and history major with a scraggly beard, wants to know whether Mosier has any idea how Clark can keep playing on his beloved women's rugby team now that he has transitioned. "Nah, man, you know the NCAA says you take one shot, you get disqualified," Mosier says of testosterone, adding, "even though we know that one dose doesn't do anything."

Mosier asks whether Clark has considered the men's team. "They all know me from before I transitioned, when I was appearing more feminine," Clark says, "and they're so freaking homophobic." Mosier is sympathetic: "I know, it's crazy! They wear those short shorts! But yeah, it sucks. There's still rec league."

Like Clark, Mosier faces uncertainty over whether he'll be able to compete in his sport. The International Triathlon Union, which runs the world championship, does not publicly list a policy on transgender athletes, and Mosier has yet to receive an answer to his request for clarification. He is concerned that the ITU will follow the International Olympic Committee's guidelines, a possibility Mosier describes as the "worst-case scenario." He says that the IOC criteria are discriminatory and "not relevant to athletic performance" -- and that they could bar him from competition.

Early-morning training is standard for Mosier, who is typically out before the sun is up. Benedict Evans for ESPN

FOR A LONG time, "athlete" was the only label that fit Mosier comfortably. When he was 8, growing up in a Chicago suburb, he started taking adult karate classes three times a week. At 10, he got his black belt and began teaching the adult class; he remembers appearing on the front page of a Chicago newspaper under the headline "The New Karate Kid."

Mosier has always presented himself as masculine, and people frequently asked whether he was a guy or a girl. "It felt good in a way, like a confirmation of something," Mosier says, "but what felt bad was watching my mom's reaction of discomfort." Mosier thought he would grow up to be a man. "I never envisioned myself in female clothes, never pictured myself getting married, having the dress, how a lot of young girls do. I always pictured myself with a flat chest and washboard abs."

When he headed to college, Mosier threw himself into activities, editing the school paper, leading a coed service fraternity, hosting a radio show, playing intramural sports and performing as Wildcat Willie. "I was always moving from group to group, never getting too close. I didn't want to have strong relationships because I was uncomfortable with myself," Mosier says. "Everyone else was questioning what I was, who I was, but I never put the time into figuring that out. I didn't identify with female, but I didn't have the language to understand what that was for me."

Mosier knew of no trans people at NMU. "My experience with trans people was Jerry Springer and Maury Povich or men in dresses for comedy. None of that was positive, and it was mostly male to female."

Mosier dated men until his senior year, when he met Zhen Heinemann, who is now his wife. After graduation, he moved to LA, Chicago and then, at age 25, New York City. In 2008, at 28, he returned to Chicago to run his first marathon. Once he completed that goal, he thought, "What's next?" So he bought a bike, and he taught himself to swim from books and videos.

Within a year, he ran his first triathlon, winning the first-timer's bracket for women at a race on Staten Island.

At the same time that Mosier was getting more serious about his athletic career, his issues around gender identity were coming to a head. After college, Mosier thought "maybe I can identify as androgynous and exist in this body and ask people not to use pronouns with me, or maybe I can be OK with people calling me he 40 percent of the time."

But living in an in-between place didn't work. "Every time people would call me she or ask 'What are you?' my power meter would go down," Mosier says. "At the end of the day, I was just broken."

Heinemann insisted that Mosier seek therapy. In counseling, he talked about how a transition would affect his family and work, but he kept coming back to sports. "Playing sports and being competitive was so important to me," he says. "If I transition, will I be competitive as a man? Will I not be allowed to compete because of my presentation? What if I don't pass as male?"

He eventually decided it was more important to be comfortable in the rest of his life, regardless of what happened with sports. By the time Mosier enrolled in NYU's graduate program for higher education in January 2010, he'd begun transitioning and entered as a man. He changed his gender designation on documents and trained with the men's cycling team. In mid-2010, he started testosterone, and by year's end, he was competing as a man. He also sent an email to all his Marymount colleagues announcing his transition.

Mosier thought a lot about whether to be out when he transitioned or to live his life "just as a guy" -- to be known as just an athlete instead of as a transgender athlete. But he says he felt obligated to come out based on his experience growing up. "I want to be the person I needed 15 years ago," Mosier says. "In terms of me saying, 'This is my identity; where do I fit in? What's your organization's name-change policy? Are there gender-neutral locker rooms?' I am setting up systems in place so other people can navigate with greater ease because I have already done it."

During his transition, Mosier blogged on a website for trans men called Original Plumbing on his fears about passing, competing in body-conscious spandex and changing in group tents during triathlons. Now, he says, most of these concerns no longer feel like an issue. The biggest surprise, Mosier says, was that when he started competing as a man, "no one cared. That's part of the super interesting thing -- no one gave me a hard time."

Female transgender athletes, such as MMA fighter Fallon Fox, are often subject to harassment and threatened with exclusion. One reason Mosier thinks he didn't get pushback is that it was widely believed that someone who transitioned from female could not be competitive against men. "There was an assumption that I would move over and not do very well, so no one paid attention to me, which was fine and great," Mosier says. But he is in fact competitive with other men. Mosier regularly places in the top 10 percent of his age group.

As part of his transition, he began testosterone therapy at about the same time he upped his training. Although the hormone has helped him build muscle faster and easier, he says, "It's hard to say how much of my performance is me waking up at 5 a.m. and training my ass off and how much is related to testosterone."

His longtime teammate and co-coach from the Empire Triathlon Club,Alison Kreideweis, says, "I don't think it's about advantage or disadvantage. It's really just that guy tries harder than everyone else."

On June 6, Mosier competed in the U.S. sprint duathlon national championship in Minnesota. Zhen Heinemann

ON A TRAINING ride in 2010, before Mosier was competing against men, a teammate suggested that he compete in the women's duathlon national championship to see whether he could qualify for Team USA. The idea stuck. "Every time I passed the same point on the road where he mentioned that -- it was next to a wood bus shelter in a small town near Nyack -- I could hear him saying that to me," he says.

Mosier never attempted to qualify for the national team in the women's division, but by 2014, he felt he could qualify for Team USA as a man. Mosier had already contacted the U.S. Anti-Doping Agency to ensure he would be in compliance with its requirements for transgender athletes. Mosier documented his hormone levels for the USADA to verify that they were within normal male range and subjected himself to random testing. He set out to enroll in the national championship race in the 30-34 bracket (triathlons are grouped by age), scheduled for July in St. Paul, Minnesota.

"Age-group athletes can get away with participating without going through those official steps, but I want to make sure everything is in order so there will never be a case where I win something and people contest it," he says.

But the process of making the doctor's appointments and getting the test results he'd need to obtain a therapeutic use exemption for testosterone took longer than expected, and then the USADA needed 21 days to reach a decision. Mosier didn't find out until the Friday before the race that he was eligible to compete -- too late for him to make it to Minnesota. "I was a little heartbroken," he says.

So Mosier marked the 2015 race on his calendar and pegged all his training goals to making the top 18, which was the cutoff to qualify for the national team. "I really structured my season around the one race. That was my only goal for this year."

In April, two months before the race, Mosier was surprised to learn that USA Triathlon had changed the qualification standards for the world championship: Only the top eight finishers in his age bracket, now 35-39, would qualify for Team USA.

Mosier looking at the result sheet with his time in the national championship. His 1:02:45.48 finish put him in seventh place for his age group and on the national team. Zhen Heinemann

Mosier is a nervous racer, and for a month or two all he thought about was making the national team. "Every time I rode my bike to commute or run errands, I would think about the championship and envision myself racing," he says. "I raced that race 400 times before I actually got to the starting line."

Finally, this past June, Mosier and his wife drove nearly 1,200 miles to Minnesota for the championship. Race day dawned sunny and clear, and by the time Mosier reached the starting line, a knee injury that had been bothering him for months magically eased. Two-thirds through the race, as he pulled into the transition area between the cycling leg and the second run, he surveyed the number of bikes in ahead of him and figured he was in the running to nab one of the final spots. But he couldn't be sure. After crossing the finish line, he made his way to the timing table to grab the piece of paper with his finish results. Without so much as peeking at it, he walked away from everyone else to be by himself. Finally, he peered down: It said he placed seventh. He was a member of Team USA. Mosier couldn't stop smiling and looking at the number.

AS SOON AS Mosier qualified for Team USA, he reached out to the ITU to find out what it would require to clear him to compete in the world championship, but he never received a definitive answer.

Across sports organizations, policies on transgender athletes are wildly inconsistent. On the high school level, some states permit students to compete as whatever gender they identify with, some require athletes to change their birth certificate and some have no policy at all. A state legislator in South Dakota recently introduced a measure that would require transgender high school athletes to submit to a "visual inspection." The NCAA came out with a policy on transgender athletes in 2011 that requires a year of hormone therapy but not any surgery.

Many sports organizations default to the IOC's guidelines on transgender athletes. The group has a long and checkered history on issues of gender. In the mid-1960s, IOC officials required women to appear naked and submit to gynecological exams to prove that they were really women. Even today, the IOC tests naturally occurring hormone levels in some female athletes. If a woman's body naturally has a high level of circulating testosterone -- something that is highly variable and that, unlike synthetic testosterone, has never been shown to confer an athletic advantage -- she can be disqualified from competition.

In 2004, the IOC, ahead of many institutions, published guidelines on what criteria transgender athletes should meet in order to compete. In a rhetorical flourish, these were officially dubbed the "Stockholm consensus on sex reassignment in sports." Among other things, the Stockholm Consensus calls for any transgender athlete to have had a gonadectomy and reconstructive genital surgery two years before competing. Genital reconstructive surgery is expensive, rarely covered by insurance and not desired by a significant portion of transgender people. Transgender advocates say requiring the surgery is unfair because the operation doesn't affect athletic ability in any way.

"Some people are comfortable with their bodies and they don't want to do that," Mosier says. "Their ability to compete as athletes shouldn't be contingent on adding or removing body Parts." (According to a statement from an IOC representative, "The IOC has always taken great care that such sensitive issues are dealt with by broad consensus using the latest scientific knowledge and research in that area.")

Technically, the IOC doesn't enforce the Stockholm Consensus itself but offers its guidelines to all the world's international sports federations, from track and field to swimming to soccer. It's up to those groups to enforce the guidelines, if they so choose, an IOC representative explained to ESPN in an email. Many adopt the IOC's position -- because it was the first and because it carries the imprimatur of the Olympics.

The effect is that, although the IOC drafted the rules, it kicks the can on enforcement to groups such as the ITU.

When contacted to clarify the ITU's policy on transgender athletes, a representative emailed that the group does go by IOC policy: Transgender athletes must be two years post-surgery before competing.

But the ITU also said that, similar to the IOC, it does not actually enforce the guidelines itself. Instead, it relies on the national federations, such as USA Triathlon, to ensure that all IOC requirements are met when they enter their athletes into international competition. So the ITU kicks the can down another level.

For its part, USAT also says that it follows IOC guidelines -- a representative for the group told ESPN that it applies them to all 4,400 events it sponsors in America. In theory, that would have barred Mosier from competing and ever making Team USA. But when asked how USAT actually goes about enforcing its policy, a representative said the group allows people to compete in the gender that is on their driver's license. In many states, it's possible to change the gender on your driver's license without surgery. In other words, USAT says it requires transgender athletes to have had genital surgery but so far hasn't enforced that policy.

That would seem in conflict with the ITU's requirement to follow IOC guidelines. But according to an email from the ITU representative, that's OK: "If USA Triathlon uses the driver's license as an indicator of the legal recognition of an athlete's assigned sex as conferred by appropriate official authorities, then that is accepted by ITU."

This bizarre chain of policies and non-policies would seem to allow Mosier to compete in Spain, albeit technically in breach of rules. The problem, as Helen Carroll, the sports project director for the National Center for Lesbian Rights, points out, is that whether the policy is enforced could change at any minute.

Carroll isn't even sure all these bodies realize how circular and convoluted their rules are. "They are not concerned about transgender men participating in international sports," Carroll says, "so they don't even realize that what they are saying does not match up."

In November, the IOC will revisit the Stockholm Consensus and, according to a representative, update its guidelines "based on the latest scientific evidence."

Nobody knows exactly what the IOC will do. But Carroll says the current IOC policy barely even mentions male transgender athletes in the first place. "The IOC is very concerned about a woman athlete having a penis," Carroll says. "Officials in men's sports don't believe a person born a female could ever be talented enough to be super competitive as a transgender man."

Chris Mosier, she hopes, could change people's minds. "I think Chris is going to blow them out of the water."

Sports bureaucrats might still be trying to figure out how transgender athletes fit in, but in a way, Mosier has already answered the question.

One morning in September, he woke up at 4:45 a.m. and ran three miles to a pedestrian bridge connecting upper Manhattan to Randall's Island. There, he fell in with a group of about 40 other members of the November Project, a hyperenergized workout group. Through a drizzle, they ran back and forth across the bridge and blasted out burpees, lunges and squats while a boom box pumped hip-hop. As is the group's custom, members frequently hugged, high-fived and whooped. When the workout finished, Mosier hand-clapped everyone as he began his run back to his apartment. This was his tribe, people who wanted to push their bodies to the edge of what's possible and see whether the body in all its finitude and disappointments can match, however briefly, the boundlessness of the spirit inside.

He could not have been more at home.