More than a quarter of men surveyed in a study in South Africa said they had committed rape.  Nearly half the respondents said they had raped more than once.

Nearly 28 percent of the men surveyed by the South African Medical Research Council said they had raped a woman or a girl, with nearly five percent saying they had done so in the past year.

Men also admitted to raping their partners, participating in gang-rapes, and some raped other men or boys.  Nearly ten percent said their first experience of coercive sex was when they were ten or younger; and most raped for the first time before age 20.

Rachel Jewkes, the director of the Council's Gender and Health Research Unit, said the study showed that men who rape, generally also engage in other risky behaviors.

"They are more likely to be physically violent towards women, they are more likely to have had multiple sexual partners,  [some] that I looked at having more than twenty sexual partners; having transactional sex, sex with a prostitute, [and engage in] very heavy alcohol consumption," said Jewkes.

Jewkes notes that many men who rape had childhoods where one or both parents was absent, where there were poor parent-child relationships, or where they experienced physical, sexual or emotional abuse. In addition she says, many of the men who rape grow up poor and with few prospects of building productive lives.

"And I think one of the ways in which we see violence towards women and violence towards other men, sort of developing as an idea and legitimated, is within a context where men feel they don't have avenues to express themselves as successful men in more benign ways through having jobs, having families, homes, through feeling good about themselves in the sort of conventional way that is accessible to men who are in a much higher income bracket," said Jewkes.

South African society is overwhelmingly patriarchal and Jewkes says this has contributed to a skewed view of manhood.

"Well we certainly have a dominant idea of masculinity that is really rooted in our overall patriarchal society and that idea is based on the fact that men are superior to women, and that men should be leading women, men should be in control of women, and one way in which men demonstrate the control is through the idea they should be able to get any woman who they want to for, you know as a girlfriend or for sex," she said.

Jewkes said they were surprised to find that men who rape are no more likely to be HIV-positive than those who do not.  However she says that because violence is so often associated with rape, the chances of transmitting HIV in a rape encounter are increased.  Consequently she says that treatment of rape victims should always include post-exposure prophylaxis against HIV.

The survey of 1,738 men between the ages of 18 and 49, from all race groups and across different socio-economic groups, was done in three districts of South Africa's Eastern Cape and KwaZulu/Natal provinces.  The survey was conducted using digital recording devices to ensure the anonymity of the respondents.