Gender archaeology is a method of studying past societies through their material culture by closely examining the social construction of gender identities and relations. Gender archaeologists examine the relative positions in society of men, women, and children through identifying and studying the differences in power and authority they held, as they are manifested in material (and skeletal) remains. These differences can survive in the physical record although they are not always immediately apparent and are often open to interpretation. The relationship between the genders can also inform relationships between other social groups such as families, different classes, ages and religions. Feminist theory in gender archaeology has presented a new perspective and introduced some biases in the overall archaeological theory. This new perspective that focused on feminist viewpoint in archaeology was initiated by the rapid evolution in the 20th century, of the Western Societies outlook and interpretation of gender. The development of this perspective commenced from the late 1960s feminist movement. Archaeologist Bruce Trigger noted that gender archaeology differed from other variants of the discipline that developed around the same time, such as working-class archaeology, indigenous archaeology, and community archaeology, in that "instead of simply representing an alternate focus of research, it has established itself as a necessary and integral part of all other archaeologies." Theory Sex and gender are often used interchangeably in archaeological research. This dismisses the cultural constructiveness of gender by connecting it to the biological perspective of sex. Gender is present in material culture and can display how a culture was socially constructed. Archaeologists emphasizing the gender and sex dichotomy reject gender exploration within a culture and advances gender determinism. Furthermore, it promotes ethnocentrism by mirroring Western gender tradition in ancient cultures. The feminist theory of gender archaeology gave archaeologists a new perspective of the past. This modern structure for theoretical perspective addressed many of the patriarchal biases instilled in the interpretation and excavation of past archaeology. Modern methods "treat gender as a process, not a thing". The new gender studies introduced biases in archaeological theory. This shift of focus is theorized to be from the increase in women in the archaeological field and from the change in the social interpretation of gender. Women archaeologists began in the last twenty years, focusing on how the gender roles of our ancestors are not being represented correctly and also the gender roles were not as rigid as once believed.