Ideas of "appropriate" behavior according to gender vary between cultures, although some aspects are more widespread than others. For example, in most current and known historical cultures, martial combat has been seen as mostly (or only) appropriate for men, while child-rearing has been seen as mostly (or only) the domain of women.
Other aspects, however, may differ markedly with time and place. In pre-industrial Europe, for example, the practice of medicine (other than midwifery) was generally seen as a male prerogative. However, in Russia health care was more often seen as a feminine role. The results of these views can be seen in modern society, where European medicine is most often practiced by men, while the majority of Russian doctors are women.
Considerable debate exists as to whether gender roles are biologically mandated, in the sense of the behavioral traits arising primarily from the biology of gender; or culturally mandated, in the sense of behavioral traits arising from early socialization. As with many such debates, most researchers believe that both factors influence the development and propagation of gender roles. However, the relative influence of each, and the specifics of how that influence operates, are still hotly disputed.
In the early 20th century, western gender roles were based around the idea of heteronormativity, and as such they were comparatively fixed. People who transgressed gender roles, such as a woman with a high-powered job, frequently experienced disapproval and discrimination.
After the sexual revolution, gay liberation, and feminism movements of the mid to late 20th century (the 1960s in particular), new roles became available in Western societies, and gender roles became rather more flexible. Narrowly defined gender roles, such as those listed here, are generally recognised as stereotypes.
Unisex means the same for both sexes, and refers e.g. to clothing.