This is more about a common prejudice (or not) about fraternities than about some famous claim. I want to know whether frat members rape more than the common non-fraternity member?
The Women Sexual Victimization study (Fisher, Cullen, & Turner, 2006), in a sample covering over 4000 women across the United States, indicates that women report instances of Rape at around 3.5% before University and 11% after university. There is sufficient evidence to suggest a concerning trend regarding sexual victimization at University.
You should check out Bannon, R. S., Brosi, M. W., & Foubert, J. D. (2013). Sorority women’s and fraternity men's rape myth acceptance and bystander intervention attitudes. http://www.degruyter.com/view/j/jsarp