There can be no equality where there is difference. Difference is not natural, it is socially constructed and enforced. Men are above women, and each have assigned roles in society, such as men do the productive work and women do the reproductive work. As a result of this enforced, hierarchical difference, women are denied civil rights.
Psychoanalysis is an example.
Supposedly there is one Unconscious, it is heterosexual, and if one deviates from what psychoanalysis says is normal, then they are sick and need to be cured by psychoanalysts. One has to speak in the terms of the straight mind when using the dominant language. It is based on flawed studies, unreliable methods, etc. Such as, when we compare our society to baboons and assume their behaviors are somehow related to us because we evolved from them, and that they are a more primative type of us. In fact, baboons and people are not comparable.