Washington - After training in a gender-violence prevention programme, Kenyan boys and young men were three times more likely than their untrained classmates to report that they'd successfully intervened to prevent an assault on girls or women, a new study found.More than 1 200 male high school students in the slums of Nairobi spent 12 hours in a six-week gender-violence educational programme called Your Moment of Truth.Nine months later, they reported stepping in to stop sexual and other assaults 79% of the time. In contrast, 293 male students who did not get the training reported intervening to thwart violence 26%, or less than one third of the time.One of the boys who took the class told his teacher he used what he learned to intercede in what he believed was about to be the rape of a toddler, lead author Jennifer Keller told Reuters Health. When the trained student saw a man starting to remove the toddler's diaper, he yelled and stopped the expected assault, said Keller, a psychologist and professor at the Stanford University School of Medicine."These types of moments of truth define our character," she said. "Shouting out to someone and saying, 'Hey, don't do that,' can really change the course."The Your Moment of Truth training is one piece of a sexual-assault programme called No Means No Worldwide, designed by Dr Jake Sinclair and Lee Paiva, two of the study's authors.The couple, Americans working in Kenya, developed the curriculum to alter male attitudes towards females, promote gender equality, develop positive masculinity and teach boys to safely and effectively intervene in gender-based violence.Unique needs Young adult Kenyan men with at least 250 hours of instruction taught the programme. It focused on the unique needs of high school boys living in Nairobi.In Kenya, 29 percent of females reported being a target of sexual violence in the preceding year and 43% reported experiencing gender-based violence between the ages of 15 and 49, the authors write in the Journal of Interpersonal Violence.Prior interventions have focused on after care for victims, they write.Jocelyn Hollander, a sociologist at the University of Oregon in Eugene who was not involved with the study, called the results "impressive.""It's promising," she told Reuters Health. "We really need a culture change to solve the problem of reducing violence. A lot of people say we should be focusing on women because they're the ones at risk, and a lot of other people say we should be focusing on men because they're largely the root of it.""And this is a great example that it's not either or. We need a multi-prong approach to stopping violence," she said.The young men who participated in the study were 15 to 22 years old, on average nearly 18.While the males who took the "moment of truth" classes improved their attitudes about women nine months after the study, males who instead took a two-hour life-skills class saw women in a slightly more negative way nine months later.Kenyan boys generally take the two-hour life-skills class sanctioned by the Kenyan government. The class touches on sex education, positive gender roles and personal rights.Males who participated in the gender-violence intervention programme were more than twice as likely to report successfully stopping verbal harassment and physical threats than those who took just the two-hour class, the study found.An earlier study showed that self-defence and empowerment classes for girls reduced sexual assaults among Kenyan students.In that earlier study, adolescents living in high-crime Nairobi settlements reported 38% fewer rapes 10 months after the classes began. Sinclair, who worked on both studies, said the prior curriculum worked "like a vaccine" to prevent rape.He calculated the programme cost $1.75 for each rape prevented and compared it to the $86 cost for one post-rape visit to a Nairobi hospital. Keller said she could not estimate the cost for the intervention in the current study.Hollander and Keller both said they would like to see a curriculum like Your Moment of Truth tested on college campuses and possibly in high schools as well."We really want to help change these negative attitudes that perpetuate the violence," Keller said. "We really want to give both boys and girls the power to prevent the violence together. This study shows we can influence attitudes."