We examine how the issues of gender and sexual orientation have been addressed in family therapy and identify critical issues as the field defines itself in a postmodern, inclusive era. We show how unintentional bias and creation of the category of "other" persist throughout the history of clinical practice despite a rise of interest in diversity. We suggest that family therapy approaches have been based on a view of sex-gender that creates dichotomous categories, confounds gender and sexual orientation, and limits flexibility. A postgender approach organized around a relationship model based on equality rather than gender is advocated. Obstacles to postgender practice are identified, and guidelines for practice and challenges for the future are discussed.