And what is "sex" anyway? Is it natural, anatomical, chromosomal, or hormonal, and how does a feminist critic assess the scientific discourses which purport to establish such "facts" for us? ... if the immutable character of sex is contested, perhaps this construct called "sex" is as culturally constructed as gender; indeed, perhaps it was already gender, with the consequence that the distinction between sex and gender turns out to be no distinction at all.

Butler, Judith. 1990. Gender Trouble