The inexorable rise of gender and the decline of sex: social change in academic titles, 1945-2001.

More than 30 million titles of "academic" articles, from the years 1945-2001, were surveyed for occurrences of the words sex and gender. At the beginning of this period, uses of gender were much rarer than uses of sex, and often used in the sense of a grammatical category. By the end of this period, uses of gender outnumbered uses of sex in the social sciences, arts, and humanities. Within the natural sciences, there was now more than 1 use of gender for every 2 uses of sex. The beginnings of this change in usage can be traced to Money's introduction of the concept of "gender role" in 1955 (J. Money, 1955). However, the major expansion in the use of gender followed its adoption by feminists to distinguish the social and cultural aspects of differences between men and women (gender) from biological differences (sex). Since then, the use of gender has tended to expand to encompass the biological, and a sex/gender distinction is now only fitfully observed.