Guys Look at Faces; Women, Crotch

When humans look at pictures of naked humans, men tend to look at the face before the crotch area. Women tend to look at the crotch area first...

"There are biological and evolutionary reasons for what they found. Women can tell by looking at naked men whether the guys are in the mood, Wallen said, but women's bodies don't reveal much. Which is why men home in on their faces. It's cryptic, but facial expression is one way of showing an indication of interest in and enjoyment of sex, Wallen said."

Study Finds Guys Not So Naughty, Gals Not So Noble
by Bill Hendrick
http://www.ajc.com/search/content/health/stories/2007/06/19/0620LVsexes.html