This first part of a two-part series exploring implications of the natural differences between the sexes for the cultural evolution of marriage assesses whether Kant should be condemned as a sexist due to his various offensive claims about women. Being antithetical to modern-day assumptions regarding the equality of the sexes, Kant’s views seem to contradict his own egalitarian ethics. A philosophical framework for making cross-cultural ethical assessments requires one to assess those in other cultures by their own ethical standards. Sexism is inappropriate if it exhibits or reinforces a tendency to