 Originally written in 1977 but not published until 1987, "Doing Gender" is the most cited article published in "Gender and Society".West and Zimmerman state that to understand gender as activity, it is important to differentiate between sex, sex category, and gender.They say that sex refers to the socially agreed upon specifications that establish one as male or female; sex is most often based on an individual's genitalia, or even their chromosomal typing before birth.