Producing original knowledge is the foundation of scientific progress. Originality is associated with certain skills and practices that can be trained and socialised. This study investigates how inbreeding as a career practice influences the socialisation of originality. An analysis based on a sample of mid-career life scientists in Japan finds that originality and associated practices are transferred to junior academics from their PhD supervisors, and that the inter-generational transfer of the practices favourable for originality is reinforced when junior academics are inbred. Hence, if senior academics have orientation towards originality, inbred junior academics are likely to succeed the same orientation; whereas if supervisor lack orientation towards originality, inbred juniors also lack the orientation. Thus, inbreeding can be a double-edged sword in developing originality.