GUATEMALA CITY — To join one of Central America’s fierce street gangs, Benky, a tiny young woman with heavy mascara and tattoos running up and down her arms, had to have sex with a dozen or so of her homeboys one night. She recalls sobbing uncontrollably when the last young man climbed off her and everyone gathered around to congratulate her on becoming a full-fledged member of the Mara Salvatrucha.

The gang leader ordered Benky, then 14, to rob buses, grab chains off people’s necks and even kill a girl from a rival gang. She always complied, although Benky said she was not completely sure if her rival had lived or died from the bullet she fired into her back.

“I thought it would be like my family,” Benky said of her reason for joining the gang, asking that her full name not be used.

“I thought I’d get the love I was missing. But they’d hit me. They ordered me around. They told me I had to rob someone or kill someone, and I did it.”

When she tried to leave the gang five years later, her fellow gang members shot her six times. The scars still visible on her body vouch for her story, as do social workers who visited her during the nine months she spent in a hospital.

Horrible as it is, Benky’s story is not unusual. Her lament is one heard from young women in gangs across the region, and in interviews many told similar tales of sexual initiation, beatings and being made to rob and kill to earn their place.

New evidence suggests that girls like Benky, most 18 or younger, may make up a larger share of Central America’s street gangs’ ranks than previously suspected, many of them straddling the line between victims and victimizers.

“There are a lot more women and girls than anyone imagined,” said Ewa Werner-Dahlin, the Swedish ambassador to Guatemala. “It’s a surprise to the experts and it shows that authorities have been reacting to gangs without really understanding them.”

Her government recently helped finance a study that included interviews with more than 1,000 past and present gang members, male and female, across Central America. It found that women might account for as much as 40 percent of the region’s gang membership. Other gang experts put the percentage lower.

The street gangs of Central America, which have spun a web of violence through Guatemala, El Salvador, Honduras and even the United States, are estimated to have as many as 100,000 members. Among them are only a small number of girl-only gangs led by girls, experts say. Far more common was Benky’s reality — a few young women in a sea of tough, sexually charged young men.

It is abuse in their home lives that often propels them into the gangs in the first place, and those gangs often continue the abuse under the veil of protection. The gang is their adopted family, the women say, offering what proves to be an unpredictable mix of affection and aggression.

“If a girl is getting abused by her father, the gang will step in and end it,” said Gustavo Cifuentes, a streetwise former gang member with an extensive criminal record who now works for Guatemala’s government trying to lure gang members into leading better, law-abiding lives. If the girls do not follow the directions of the leader, Mr. Cifuentes acknowledged, a beating or even worse will be the result.

Male gang members say the girls play an essential role and not just as sexual partners. They are able to move more freely on the streets when the police are around, transporting drugs or guns. And bus robberies are best done, veteran gangsters say, with a team of two males and two females, confusing passengers about who is involved.

With four jail stints behind her, Benky, now 23, is experiencing a new phase of life, but one that is proving almost as rough as all she has endured before. Her wounds have left her limping through life, selling candy on the buses she used to rob because her gang tattoos disqualify her from most other forms of employment.

Most of those who made up her gang have died in shootouts with the police, she said, but one of the few still living spotted her recently on the street and yelled out a threat on her life. He had been surprised that she had survived the attempt to kill her. “It looks so good from the outside,” Benky said about why she had joined the gang. To understand her sentiment, it helps to know that her childhood, like those of many other girls in gangs, was grim.

She began living on the streets at the age of 6 with an older brother. She is not sure what happened to her mother, but she recalls that her father had no interest in taking care of them. Her brother was shot by a member of the 18th Street gang, which prompted her to join the other giant gang in the region, the Mara Salvatrucha, she said, looking for love and acceptance.

Benky had begun hanging around the gang and knew a few other girls who had joined. They told her that all she had to do was talk to the leader and he would induct her as well. Before she knew what was happening, though, her new family members were disrobing and lining up to have sex with her.

The abuse ebbed when she began dating a gang member and he protected her from the rest.

“He was very kind,” she said. “Sometimes, he’d go out and rob buses just to get me what I wanted.”

Other girls in gangs, who also insisted on being identified only by their first names or nicknames, also complained of lives ruined, close calls with death, and nightmares about all the awful things they did for their gangs and neighborhoods. It often begins, the girls say, with group sex, their minds usually dulled with alcohol and marijuana.

Ana, 21, who spent four years as a member of the 18th Street gang, said she was given a choice between group sex and a group beating when she joined because she was friends with the gang leader’s girlfriend. “Other girls didn’t get to choose,” she said. “I thought the beating was better. I’d have a black eye and I’d be hurt but at least I wouldn’t get pregnant or get a disease.”

Her gang days were intense ones, she recalls, full of assaults and robberies and other behavior she now regards as deviant. “I learned to use a gun more or less but I was better with a knife,” she said. Her gang had a separate leader for the girls, and that tough young woman one day ordered Ana to beat up a neighborhood girl whom the leader found annoying. The girl happened to be a friend of Ana, but Ana said she did what she had to do.

Another former gang member, a 17-year-old called Moncha, broke down as she described how someone in her gang had shot her friend to death. “I lost my best friend, and my own gang killed her,” she said. “That’s when I realized that if they killed her, they could kill me, too. I got tired of living this life where they might say, ‘Let’s go kill someone,’ and you had to go along.”

Ana had a somewhat easier time than others did putting her gang life behind her. Her mother was dying from cancer, and that prompted her to move back home and care for her around the clock.

Her mother’s long illness allowed Ana to make a break. Her path was a little easier than Benky’s because she never got any tattoos to identify herself as a gang member. Eschewing tattoos is becoming more and more common as Central American governments crack down on gangs with “mano dura,” or firm hand, policies, gang experts say.

At Santa Teresa prison, a sprawling detention center for women in Guatemala City, signs of both hope and despair can be found. Bianca, 24, a tough member of the 18th Street gang who is locked up on drug charges, showed off her bold gang tattoos and spoke of protecting her neighborhood. She stood on the sideline during the jailyard soccer game put on by Guatemala’s Ministry of Culture and Sports.

But another inmate, 25, who goes by the nickname Happy, said she intended to leave the gang when she finished her sentence for robbing buses. In her first years behind bars, members of the gang would come by to visit, she said. But that eventually faded. Nowadays, five years in, it is only her mother who brings her food and clothes.

“She’s family,” Happy said. “It took years but I finally learned that.”

Copyright 2008 The New York Times Company. Reprinted from The New York Times, International, of Friday, April 11, 2008.