"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. [...]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."
Interestingly, it seems like even knowing that their eye movements were being recorded didn't affect the habit.
Side note: the main article is actually interesting, if you can manage to tear your eyes away from George Brett's groin.