Sex: an imperfect marker of gender.

As the study of sex differences in schizophrenia gains popularity, inconsistent use of terms such as "sex," "gender," "sex-related," and "sex-linked" can lead to conceptual ambiguity. I review briefly why precise terminology is important and draw the reader's attention to a well-developed literature, a knowledge of which should benefit our studies. Adoption of the term "sex" in reference to comparisons based on the demographic categories of female and male and the term "gender" in reference to comparisons of femaleness and maleness, as suggested by Kay Deaux (1993), is urged in the study of schizophrenia.