This document discusses theories of gender from the Enlightenment period to modern times. It covers key philosophers like Descartes and their establishment of mind/body and other dualisms. It also discusses the work of theorists like Freud, De Beauvoir, Stoller, Gatens, Butler, and others who have developed and debated theories of sex, gender, and sexuality. The document examines how common sense views of gender as natural have been produced through language and discourse over time.