The 1923 Greco-Turkish exchange was the first internationally ratified and executed compulsory population exchange between two countries. It set an international legal precedent whereby forced migration is legitimized as a humane solution to conflicts in order to restore social order. Informed by the principle of segregation, the 1923 exchange is thus organically related to other cases informed by the same logic: the construction of walls, apartheids, partitions, and forced migrations. It constituted a legal reference point for the Potsdam Agreement (1945), as well as the partitions of India and Palestine in 1947 and 1948. Considering the legacies of the 1923 exchange in the post-1945 era, this paper explores the politics of expertise and scholarship on post-Second-World-War refugee integration as a management of difference. Specifically, it traces the fascist fusion of demographics and eugenics in refugee management through an international refugee association presided by a leading Turkish eugenicist. Through archival research and textual analysis, this paper examines how after the Second World War, some former fascists, eugenicists and social scientists collaborate with their counterpart in Turkey and beyond to address the post-1945 refugee crisis with references to the 1923 exchange. Within this framework, it raises questions about the broader implications of qualitative demography in relation to eugenics and humanitarianism--and how these fields contributed to shaping the debates on the "refugee regimes" established after the Second World War.