A quarter of men surveyed in half a dozen Asian countries have admitted to raping at least one woman - with most saying that they regarded it as sexual entitlement or entertainment.
The survey of 10,000 men in Bangladesh, Cambodia, China, Indonesia, Papua New Guinea, and Sri Lanka found that one in 10 respondents had raped a woman who was not their partner. That figure rose to one in four when partners were included.
Led by Rachel Jewkes, head of the South African Medical Research Council, and published in the Lancet Global Health, the findings showed that half of men said they had committed some form of physical or sexual violence on women.
Survey respondents came from both urban and rural areas and were aged up to 50.
Questions included: "Have you ever forced a woman who was not your wife or girlfriend at the time to have sex?" and "Have you ever had sex with a woman who was too drugged or drunk to indicate whether she wanted it?"
Jewkes found that of the men who said they had committed rape, 45% said they had attacked more than one woman.
The prevalence of rape was highest in Bougainville, Papua New Guinea, where 24% of men said they had raped a woman who was not their partner. The lowest rate was in rural Bangladesh (3%).
Explaining why they raped, 73% said it was because of sexual entitlement, 59% said for entertainment and 39% said it was to punish the woman.
Men who were more likely to rape had a history of victimisation, physical violence towards a partner, had paid for sex or had had a large number of sexual partners.
Jewkes said: "In view of the high prevalence of rape worldwide, our findings clearly show that prevention strategies need to show an increased focus on the structural and social risk factors of rape. We now need to move towards a culture of preventing the perpetration of rape from ever occurring, rather than relying on prevention through responses.
"Our findings are of substantial global interest, partly because most of the world's population lives in this region, and partly because the countries we studied are culturally diverse.
"Effective prevention of rape and gender violence clearly requires long-term strategies, including challenging of practices that are deeply rooted in cultural ideals of masculinity and gender hierarchy.
"There is still very little evidence-based research in this area, and further work is urgently needed to establish the most effective interventions, and to determine how we can develop effective national prevention programmes."*