Transcript for Ronda Rousey, the Making of a Fighting Champion
Mixed martial arts is described as a full-contact combat sport with rules like no biting and no eye-gouging. There's no hair-pulling, either, but that goes without saying, doesn't it? So just a month ago, the most famous ultimate fighting champion in the world, Ronda Rousey, lost her first fight in a shocking upset, so why are we still focused on Ronda and not the winner? Just watch. The popular and undefeated bantamweight women's world champion. Rowdy Ronda Rousey. Reporter: Ronda Rousey is ferocious. And there she goes! Reporter: She's been called the best female athlete ever. Are you kidding me? Reporter: But her accomplishments defy gender. In fact, she makes more money than any ufc fighter, male or female. When she enters an arena before a fight, she says she feels like Superman stepping out of his phone booth. But even Superman has his kryptonite. Ronda's came in the form of a preacher's daughter from Albuquerque named holly Holm. Vegas put the odds at 12 to 1 in favor of Rousey. And all it took was one kick. Beautiful. Can she get out of it? Beautiful. She's hurt and in trouble. She's hurt! She's out! Holly Holm is the new ufc -- Reporter: She spent the night in the hospital. Just like that, the superhero became human once again. All the best things of my life have happened as a direct result of the worst things that ever happened. And every missed opportunity has been a blessing in disguise. Reporter: If you'd never seen a Ronda Rousey fight before that one, you might wonder what all the fuss was about. Want to see one now? Have you got 14 seconds? Ronda wants to make it happen quickly. She gave up her arm. There's the arm! There it is! She tapped! All over! Oh, my god. Just like that. Reporter: That's all she wrote. Ronda! Reporter: In one year, she went from "Ronda who?" To feminist folk hero. Please welcome Ronda Rousey. Reporter: She is the toast of talk shows. Okay, ready? No. Reporter: Twist her arm, and she'll show you how she twists arms. What? Rumpelstiltskin. Very good. Rumpelstiltskin! Reporter: She's called the arm collector. Her arm bomb move is said to be so painful that when she collects yours, game over. She's trying for it. Reporter: Women, she says, fight for different reason than men. For women, it's meaner, more vicious, a blood sport. And for Ronda, every fight is personal. It's been a fight from the beginning. An umbilical cord wrapped around her neck at birth gave her apraxia, a disorder that it impossible for her to form intelligible sentences for her first six years. She was named Ronda after her dad, Ron, who suffered deteriorating health after he broke his back in a sledding accident near their home in North Dakota. When Ronda was eight, he killed himself. It was hard. And he was gone, and we were alone. If there's one thing about my backstory that is the most well-known fact, it's about what happened to my father and it's like -- it's still hard for me to talk about. It's still, like, an open wound for us, you know? Reporter: Her mother, annmaria, had been a judo champion. Here she is at the 1983 pan American games. She became Ronda's trainer and gave her daughter the eye of the tigress. My first injury was I broke my big toe. And she was like, "You got nine other toes. Tell me when you got one left." Reporter: Ronda wanted to be an olympian in judo, qualified for the 2008 games, and won a bronze medal. Most would have celebrated. Ronda was heartbroken. Missing out on olympic gold is what keeps me motivated to come back and defend my belt over and over and over again. Reporter: Her dream didn't die that day. It changed. At age 22, she switched to mixed martial arts, a fast-growing sport that is both dangerous and brutal. From this "Sports illustrated" glamour shoot, you can see why Hollywood is calling. Hey. Just wanted to say thanks. Reporter: They're going to make her an action star, and that's okay with her. They also want her to lose weight, be a little more feminine. Imagine how that meeting went. Just because my body was developed for a purpose doesn't mean it's masculine. I think it's femininely badass as Because there's not a single muscle on my body that isn't for a purpose because I'm not a do-nothing bitch. Reporter: No doubt about that. Ronda always had something to prove to herself. Champion of the world! Reporter: But now, she has something to prove to the world and to the preacher's daughter. A rematch is inevitable. And I wouldn't count her out. After all, Ronda fights for a different reason, and she has redefined what it means to fight like a girl.
This transcript has been automatically generated and may not be 100% accurate.