This chapter analyzes the social forces and the ways in which eugenics is shaped and accommodated in various scientific disciplines. It explores Japanese cultural impacts and imperialism shaping Chinese scientific disciplines in general and eugenics in particular. The chapter discusses the American and Nazi Germany connections of the eugenics movement, as well as the formation of the scientific community and disciplinary establishment of biology and medicine in both Japan and China in which eugenicists struggled for social recognition and disciplinary turf. With limited resources, their competition strategy of converting local materials with modern scientific language into usable data in order to fast gain recognition, resonated with other local scientists in biology and medicine. In medicine, the demand of localization forced Peking Union Medical College and the Rockefeller Foundation to steer away from the original trajectory of scientific medicine as their medical mission.