Why does the world have the pattern of patriarchy it currently possesses? Why have patriarchal practices and institutions evolved and changed in the ways they have tended to over time in human societies? This paper explores these general questions by integrating a feminist analysis of patriarchy with the central insights of the functionalist interpretation of historical materialism advanced by G. A. Cohen. The paper has two central aspirations: first, to help narrow the divide between analytical Marxism and feminism by redressing the former's neglect of the important role female labor has played, and continues to play, in shaping human history. Second, by developing the functionalist account of historical materialism in order to take patriarchy seriously, we can derive useful insights for diagnosing the emancipatory challenges that women face in the world today. The degree and form of patriarchy present in any particular society is determined by the productive forces it has had at its disposal. According to historical materialism, technological, material, and medical advances that ease the pressures on high fertility rates (such as the sanitation revolution, vaccinations, birth control, and so on) are the real driving forces behind the positive modulations to patriarchy witnessed in the twentieth century.