A clear distinction was drawn in women’s and gender studies research in the 1980s between “sex” and “gender”. A pioneering discovery at that time was that differences between women and men could be explained not only in terms of physical differences in the body, but predominantly with reference to social factors. In the meantime it is clear that no clear separation is possible between “sex” and “gender”. On the one hand, the separation results, if the focus is only on social gender, in biological femininity and masculinity remaining unquestioned as a “natural” fundament. On the other hand, a separation between biological sex and social gender ignores the fact that our view of what is biological is heavily affected by what we regard as such socially. In the history of medicine, many quite different views are expressed as to what “biological” sex actually is, and it is only with the rise of the two-sexes model that the biological view has been established that there is such a thing as “man” and “woman”. Nor, however, can this biological order necessarily be translated into a sharply divided social order. Consequently, it is useful to think simultaneously in terms of biological, social and cultural factors. The important question is why classifying people into women and men is relevant and how the differences are evaluated in social terms.

So “gender” describes social gender as an interplay between biological factors such as a set of chromosomes, between physical factors, such as height, appearance, pitch of voice, between social factors, such as naming, which, under German law at any rate, has to indicate a clear allocation to one gender, education or division of labor with regard to certain gender roles, or the experience of being addressed and classified as a man or a woman because of certain clothes, height or hair style.

As a term, therefore, gender stands for a shifting understanding of sex within certain social contexts. Gender is not a “natural” given. The fact that there are women and men and that they are perceived as two different groups of human beings is primarily the result of a series of social attributions and expectations communicated through education, media, role expectations and norms. So biological sex is not the basis of gender, but is always part of gender. The way in which women and men “embody” their gender and what is taken to be “natural” and “normal” is thus always dependent on social conceptions and norms. This means that even sex, which is taken to be “natural”, has a history, for the scientific and medical view of the body is also subject to change over time.