Monogenism or sometimes monogenesis is the theory of human origins which posits a common descent for all human races. The negation of monogenism is polygenism. This issue was hotly debated in the Western world in the nineteenth century, as the assumptions of scientific racism came under scrutiny both from religious groups and in the light of developments in the life sciences and human science. It was integral to the early conceptions of ethnology.
Modern scientific views favor this theory, with the most widely accepted model for human origins being the "Out of Africa" theory.