A review analysis of 13 studies — encompassing more than 13,000 individuals — found that there were more differences in personality, behavior, and preferences from one woman to another woman, and one man to another man, than there were between men and women as groups. In other words: The opposite sex isn't an alien life form. Men and women are both from Earth, not Mars or Venus. Diversity abounds, but you can't really classify those differences as "women are like this" and "men are like that". Instead, it's more like "this person is like this" and "that other person is like that".