“I’ve been a fighter my whole life,” said Smith, who is 35. He was born in Cincinnati, but his family moved to San Bernardino on his 8th birthday. They were poor. His father worked an assortment of jobs, including preacher and small-time professional boxer. He taught Smith and three of his brothers how to handle themselves and took them to the local Boys’ Club for boxing lessons. They were the only white kids, Smith said, and the Latinos and African-Americans at the club teased them about their Midwestern accents.

Image Credit... Andres Serrano

But most of Smith’s childhood fights took place outside the ring, on the streets and at his instigation. He used to wear his hair in a mohawk as a tribute to the professional tag-team wrestlers the Road Warriors and prowl the neighborhood looking for fights. “I was just mad-dogging everyone”  staring them down  “until somebody said something, and then I’d put my hands up and start fighting.” He said he had 46 counts of assault and battery as a juvenile. “And that’s 46 counts posted on me. Can you imagine how many there actually were?”

I asked Smith why he spent so much of his youth looking for trouble. I expected some sort of clichéd, though possibly true, explanation  a difficult childhood or a Napoleon complex. What I didn’t expect him to say was, “You know, bro, the sexual-preference thing.”

Smith is gay, and I know of no other professional fighter who is openly so. “I was always scared that my mom and dad would find out and wouldn’t like me, and my brothers wouldn’t like me,” he said. “I was petrified, because I didn’t want anyone to find out. And I would try to be the toughest person around. That way, no one would suspect, no one would ever say it, no one would think it.”

On Nov. 12, 1993, the Ultimate Fighting Championship made its debut in Denver, billing itself  much as Felony Fights does now  as a no-holds-barred brawl. In fact, there were a few rules  no eye-gouging, no biting  but victory, according to the promoters’ hype, could be earned only by “knockout, surrender, doctor’s intervention or death.” There were no weight classes and no gloves. The basic conceit of the early fights, held in an octagonal cage, was to answer the eternal adolescent questions that served as the basis of Jean-Claude Van Damme’s Hollywood career. Could a boxer beat a wrestler? How about a kickboxer versus a judo champion?

The sport’s immediate influence was Brazilian vale tudo  “anything goes” in Portuguese  but the U.F.C.’s owner, a pay-per-view production company called Semaphore Entertainment Group, invoked the spirit of Roman gladiators in its marketing. A more accurate historical parallel is pankration, the most popular event of the ancient Olympics. “Pankration was a savage all-out brawl, where only eye-gouging was banned,” Tony Perrottet writes in “The Naked Olympics,” his popular history of the ancient games. “The more brutish participants would snap opponents’ fingers or tear out their intestines”; the judges approved of strangling. Some competitors accepted death rather than surrender.

Many regarded ultimate fighting as barbaric. Among them was Senator John McCain, who helped persuade dozens of states to ban events and major cable pay-per-view providers to stop showing them. For a few more years, the organization sputtered along as the owners tried to appease their critics, introducing gloves and a few more rules  no hair-pulling and no kicking the head of a grounded opponent among them  while courting state athletic commissions. In late 2000, New Jersey became the first state to hold a sanctioned mixed-martial-arts event. But it was too late for Semaphore, which, facing bankruptcy, sold U.F.C. the next year for $2 million to a company owned by two casino executives. A small-time boxing manager, Dana White, was put in charge.