Courtesy of Feministing, we have a report from the Online Journalism Review that, when looking at a picture, women look first and longest at the face. Men tend to take in the whole, well, package.
Although both men and women look at the image of George Brett when directed to find out information about his sport and position, men tend to focus on private anatomy as well as the face. For the women, the face is the only place they viewed.
Coyne adds that this difference doesn’t just occur with images of people. Men tend to fixate more on areas of private anatomy on animals as well, as evidenced when users were directed to browse the American Kennel Club site. (my emphasis)
For the record, guys, when you spend all that time at Hooters "just stretching" and "just popping your neck," we know what you're doing. We just never thought you were checking out dudes.