This book examines language and communication in a novel area of digital health. Situating itself within the sociocultural paradigm of literacy research, the book proposes a discourse-oriented approach to genetic literacy and applies it to the study of public engagement with direct-to-consumer (DTC) genetic testing—an emergent biotechnology operating at the intersection of personal genomics, consumer culture, and online health. The author draws on a rich dataset comprising marketing materials from a leading genetic company in China, interviews with genetic test users, and online forum interactions involving consumers and members of the genetic company. Using in-depth analyses of authentic discourse data, the book examines how key stakeholders in DTC genetic testing discursively construct and negotiate socially situated knowledges about genetics and health to pursue a range of interactional goals. Challenging the static and cognitive view of genetic literacy as a set of decontextualised knowledge and skills in scientific and medical fields, this book argues for a reconceptualisation of genetic literacy as a dynamic and socially situated discursive practice. Building on key insights from medical sociology, the author discusses genetic literacy within the context of broader societal shifts, including the biomedicalisation of health and the rise of neoliberal ideologies and practices in contemporary healthcare. Written in a clear and accessible style, this book will appeal to researchers and students working in the areas of sociolinguistics, discourse analysis, and health communication. It will also be of particular interest to practitioners in genetics and health, as well as members of the general public seeking to understand the social aspects of public engagement with genetics and health.