There are two bibliographies on the Home Page that list many articles about male sexual abuse. Some of them (for example, Mendel, Gartner) detail the issues and problems related to researching the topic. The 1 in 6 figures come from the 1995 article by Lisak, Hopper, and Song. That was based on a random sample of 600 college age men (mean age 28), but Lisak now has data on about 3000 men. He found that 17% said they had had unwanted direct sexual contact with an adult or clearly older child by age 16. ("Direct" means that touch of some kind was involved.) When indirect sexual contact was included (like asking a child to pose for pornography) the figure rose to 28% (1 in 4). The figures for women come from studies by Diana Russell in the 1980s.