Using a post-structural approach, feminists seek to uncover (or deconstruct) the ways in which gender and all aspects of social interactions have been structured by a historically male-dominated way of thinking. These social interactions include economics, race, gender relations, gender roles, and language itself. While feminism originated as an ideology of supporting women and demanding equal rights, the post-structural approach to feminism seeks to dissect the various ways women have been marginalized; in other words, to reveal the bias in those structures.
For example, Julia Kristeva has used a psychoanalytic approach to study the unconscious aspects of language that structure the way we think about social relations. Judith Butler, in Gender Trouble, has noted that structures such as gender are cultural constructions which are therefore not essential.
That gender reality is created through sustained social performances means that the very notions of an essential sex and a true or abiding masculinity or femininity are also constituted as part of the strategy that conceals gender's performative character and the performative possibilities for proliferating gender configurations outside the restricting frames of masculinist domination and comuplsory heterosexuality.
In short, Butler shows how gender is a performance. Therefore to be masculine or feminine is to behave in certain traditionally prescribed ways. In revealing how "being feminine" has traditionally meant staying at home, wearing a dress, being more genteel, etc., a post-structural feminist such as Butler reveals how these roles have to do with cultural beliefs; not anything essential about being biologically female. That being said, to go beyond those traditional roles is to challenge the historically male-dominated definitions of male and female.
By revealing the structures which inform our way of thinking, postmodern theorists and/or feminists expose the constructed boundaries between man/woman and other binary oppositions.
Post-structural and postmodern feminists tend to be more multi-disciplinary than their predecessors because they recognise that ideas about gender are embedded in many disciplines.