One strand of inquiry: Going into a psycho-phylogenetic history of sexuality of close relatives of Hominins to capture what natural behavior can be observed in Bonobos and baboons. The other strand, look into the wide range of sexual behavior in history: fertility cults, tribal differences to get a foundation about cultural determinations throughout the civilizatory processes (Norbert Elias oeuvre)
It depends what is your main idea. You can compare for example the sex discrimination in different countries or only in your country. But you must have in mind that the culture has significant influence on how people perceive and act about the sex discrimination. For example in my country Bulgaria there is no such visible sex discrimination on the workplace. There is many women that are managers and their salaries are not dependent on whether they are women or not. Bulgaria is on second place in EU about women who are managers.