Literature on scientific controversies has inadequately attended to the impact of globalization and, more specifically, the emergence of China as a leader in scientific research. To bridge this gap in the literature, this article develops a theoretical framework to analyse global scientific controversies surrounding research in China. The framework highlights the existence of four overlapping discursive arenas: China's national public sphere and national expert sphere, the transnational public sphere and the transnational expert sphere. It then examines the struggles over inclusion/exclusion and publicity within these spheres as well as the within- and across-sphere effects of such struggles. Empirically, the article analyses the human genome editing controversy surrounding research conducted by scientists in China between 2015 and 2019. It shows how elite scientists negotiated expert–public relationships within and across the national and transnational expert spheres, how unexpected disruption at the nexus of the four spheres disrupted expert–public relationships as envisioned by elite experts, and how the Chinese state intervened to redraw the boundary between openness and secrecy at both national and transnational levels.