Talcott Parsons was a very famous and popular sociologist in the United States. He believed in social inertia, which stated that societies would keep moving in one direction unless a massive societal force pushed or changed them into another direction. They would then keep moving in that direction until another force came along.
Talcott Parsons (1902-1979) developed a general social theory called Action theory, based on the methodological principle of Voluntarism and the epistemological principle of analytical realism. The theory attempted to establish a balance between the utilitarian-positivist and hermeneutic-idealistic methodological traditions. For Parsons, voluntarism established a third alternative btwn these two (Wikipedia).
What you're looking at is Talcott Parsons' model of the nuclear family. Brought in during the 1950's and 1960's when structural functionalism was at its peak, this model was known as the way to ascertain the duties and labor to whatever gender a person identified themselves as. Gender inequality, says the functionalist, is a way to maximize to efficiency of labor. Labor roles were predefined--women would be labeled as the main caretakers and men provided for the family.