If you want to explore the postmodern view of gender/sexuality, a good place to start is by trying to listen generously to Foucault's statement that there were no homosexuals before about 1850. The acts which today preform a queer identity were preformed before 1850 but they were not at that time gerundic in
relation to a distinct type of person. Being queer is a resistance to a regime of power which had not fully formed much before 1850. Being queer in 1800 would have been impossible for the same reason that being an anti-communist would have been impossible in 1800.  Queer discourse is a counter-discourse creating a site of resistance to the medical regime of power which takes sodomy as the gerundic expression of a pathological state of being. Before this particular
regime became the primary system of control regulating the constitution of sexual identities, being queer was not a possiblity and neither was being homosexual. One becomes homosexual by thinking of oneself within the regime that creates rigid categories of sexuality and queer by resisting this regime. In both cases, subjective experience is modified by the objective state of affairs.  None of the ancient Greeks were either homosexual or queer, not even Sappho.

      The postmodern approach to gender/sexuality defines the acts performative of gender/sexuality as being fixed in their meaning by contingent regimes. At
the rupture points between regimes, possible ways of defining oneself cease or come to be. Gender/sexuality is an artifact of the regime of power which regulates gender/sexuality. It is in this sense that our discourse about gender/sexuality is a performative in the same strict sense as the statement "I swear to ''''" is a performative utterance, making itself true in the moment of the swearing. In both cases, saying is a doing and become becoming bound to a particular characterization.

    Our performance of gender/sexuality is an expression which creates the thing expressed. This is the origin of self-knowledge or gender/sexuality as
subjectivity. This subjectivity is imbricated within a discourse about gender/sexuality which creates its own object as knowledge. The narrative element comes when we think of discourse and counter-discourse, interpollation or resistance, as stories told and stories told about those stories by some of the people those stories are about. 

See:
Foucault, The History of Sexuality
Foucault, The Use of Pleasure

Also see:
Judith Butler