In the political and philosophical context of 18th Century Europe, the idea of male supremacy could no longer be legitimately attributed to the "will of the gods"; it needed to be founded and explained in a rational way. The housekeeper who marries her employer will carry on cooking, cleaning, darning socks, etc.
From Antiquity, Aristotle, in his definition of the order of beings, and Galien, in his anatomical definition of the body, provide the basis of the single sex model which was dominant until the 18th century, and in which gender defines sex: men and women are ranked according to their degree of metaphysical perfection, along an axis in which the peak is occupied by man.
Public and private-sector employers are encouraged to offer long periods of unpaid or partially paid parental leave, directed almost exclusively at women workers.
In some cases, it is hard to define a clearly established and coherent model of state intervention. This question is central to the work of the German sociologist Birgit Pfau-Effinger Individuals gain their social citizenship rights directly through their own participation in paid labour.
As Pfau-Effinger notes, the model of social integration with differentiated male and female roles which characterised Germany at the end of the 20th century reflects the urban bourgeoisie's system of values at the second half of the 19th century.