You can't research into someone's feelings. If you were to say that you "feel" like you are neither male or female in gender, I can't prove or disprove your statement. Feelings are not fact, so I can either believe you for no reason or I can go on what most societies have believed for thousands of years. Notice that throughout history, the overwhelming majority of people believed in only two genders, and so people "identified" as male or female. Only since the idea of multiple genders became widely accepted has there been people who "identify" as male, female, both, or neither. The multiple genders thing is a product of societal beliefs rather than the other way around.