This thesis explores how young adults in China provide care for sick family members, drawing on both biomedical and tacit knowledge while navigating complex moral expectations. Based on interviews with 20 young adult caregivers and autoethnographic reflection, the study investigates how caregiving is embedded within familial roles rather than taken up as a distinct identity. Most participants did not see themselves as “caregivers,” but simply as family members fulfilling their obligations. A central analytic is guan (管)—a Chinese term encompassing care, control, and responsibility—which helps illuminate why caregiving knowledge and labor often remain invisible. Tacit knowledge, in particular, is not only difficult to articulate but often morally silenced: care recipients downplay their needs to avoid being a burden, while caregivers are expected to intuitively anticipate and respond without acknowledgement. Biomedical knowledge, by contrast, is used strategically to persuade elders or assert authority in clinical situations. By foregrounding the phrase “I cannot not guan,” this study reframes caregiving not as a voluntary act of care but as a moral imperative shaped by kinship structures. It engages with feminist Science and Technology Studies (STS), especially Maria Puig de la Bellacasa’s notion of “matters of care,” to propose a cultural and relational rethinking: what happens when care is not chosen but expected? The thesis challenges dominant frameworks in the literature on care by examining how knowledge and relational obligations are entangled in Chinese family life, and by suggesting guan as a lens for theorizing care in contexts where choice is beside the point.