Judith Butler, Gender Trouble: Feminism and the Subversion of Identity. New York: Routledge, 1999. 36-37.

In Lacan, as in Irigaray's post-Lacanian reformulation of Freud, sexual difference is not a simple binary that retains the metaphysics of substance at its foundation. The masculine "subject" is a fictive construction produced by the law that prohibits incest and forces an infinite displacement of a heterosexualizing desire. The feminine is never a mark of the subject; the feminine could not be an "attribute" of gender. Rather, the feminine is the signification of lack, signified by the Symbolic, a set of differentiating linguistic rules that effectively create sexual difference. The masculine linguistic position undergoes individuation and heterosexualization required by the founding prohibitions of the Symbolic law, the law of the Father. The incest taboo that bars the son from the mother and thereby instates the kinship relation between them is a law enacted "in the name of the Father." Similarly, the law that refuses the girl's desire for both her mother and father requires that she take up the emblem of maternity and perpetuate the rules of kinship. Both masculine and feminine positions are thus instituted through prohibitive laws that produce culturally intelligible genders, but only through the production of an unconscious sexuality that reemerges in the domain of the imaginary.