Sexual orientation
A 1970s study on masculinity and femininity says that the concepts are better on separate scales. The scales are in place of single continuous scale. Each end of the scale is representative of total opposites. When on the same scale, one will have to decrease for the other to increase. To be more feminine, one has to be less masculine. To be more masculine, one has to be less feminine. However, if they are thought of as separate areas, one can be both very masculine and very feminine. In the same way, heterosexuality and homosexuality on separate scales would allow one to be both very heterosexual and very homosexual. Or someone can be not very much of either. This makes determining the degree of heterosexual and homosexual in an individual easy. It is easy because each area is thought as independent rather than attempts to match a specific balance like the Kinsey scale.