Everyone knew Geena Rocero was a model, but they had no idea she was transgender—and had taken hormones and had surgery to be the gorgeous woman they admired. In a Glamour exclusive, she tells Susan Dominus why she risked her dream career to go public.

Geena Rocero struggled to calm herself in her Vancouver hotel room. It was March 19, the day she would be giving a talk at TED, the highly influential conference series of world thought leaders. As a model, Rocero, 30, was used to being in the spotlight, but this particular performance was like none she had ever given. She went over her speech; she obsessed about whether to wear her black YSL pumps or her strappy tangerine heels; she meditated. "What I'm about to do will change my life," she reminded herself.

Finally, it was time. In the pumps and a simple fitted dress, she walked onstage before an audience of several hundred powerhouses, including celebrities like Will Smith and Google cofounder Larry Page. "I felt like I was freeing myself to be fully as I am," she recalls. "No turning back."

Rocero started to speak about the challenge of living a life true to one's inner self. At the two-minute mark, she flashed a picture on the screen: an image of what appeared to be a little boy staring somewhat defiantly at the camera. "I was assigned 'boy' at birth, based on...my genitalia," she told the hushed audience. The beautiful woman they were looking at and the child in the photograph were the same person.

It was the first time Rocero had publicly revealed she was transgender. She'd had sex reassignment surgery at age 19, a major milestone in her life that she'd kept to herself, never sharing it with the vast majority of friends and colleagues she'd met in New York City. Over the years, as she built her career in modeling, she lived in fear that she would one day wake up to a salacious item about herself in the gossip pages: "Geena Rocero is not a woman." Not only could it cost her her career, but it would also reinforce what she saw as an ignorant misconception about transgender women—that they aren't real women. Now, at TED, in the most visible way possible, Rocero was explaining her decision to step forward: "I want to do my best to help others live their truth without shame and terror." And that day, there would be no shame. The audience cheered her announcement; she received a thundering standing ovation, and her talk would go on to generate 2 million views online.

When the news reached her agent at Next Management, Ron Gerard, he was stunned to hear the truth about the model he represented. "I had no idea," says Gerard. "It was like—boom!" But despite his shock, Gerard was supportive: "I give her a lot of credit for doing what she's done and taking a stand." Gary Bertalovitz, an agent at Images Management who had worked with Rocero earlier in her career, was equally surprised. "I didn't know, but it doesn't change anything," he says. "It's still Geena—she's a great girl." Any fear Rocero had about losing work or the respect of her colleagues was finally put to rest. She wasn't being dismissed; she was being applauded.

It was a reception she never could have imagined nine years ago, when she began modeling. Nor could she have envisioned that in 2014, transgender women and men would be making the cover of Time magazine, headlining popular shows like Glee and Orange Is the New Black, starring in ads for Barneys and Marriott—and even being embraced as coworkers and Girl Scouts and homecoming queens. A majority—89 percent—of Americans now believe transgender people deserve the same rights and legal protections as others, according to a recent study.