This chapter addresses four major questions debated by European scholars during early colonialism. Concerning the unity of the human species, generation, reproduction and descent, they were influential both in shaping what was then called the ‘natural history of man’, our physical anthropology, and in developing the racial theories of the second half of the eighteenth century and the early nineteenth. Special attention is given to the inheritance of skin pigmentation, especially in the children generated by mixed couples, since skin colour was the main physical trait of the peoples mentioned by sixteenth- and seventeenth-century travellers. It was used to establish rank as well as legal and religious rights within the colonies, and by natural historians in Europe to classify human groups. The chapter argues that while what we call racist practices were developed in the colonies, racial theories and racial classifications were mainly elaborated in Europe. It is also argued that people of mixed parentage may be considered the lasting but unintentional contribution of colonialism to proving the unity of the human species, and a visible refutation of the notion of race as a stable natural entity.