Research on autism has increased significantly over the past several decades. This upsurge parallels the steep rise in autism diagnoses. Together, these conditions have increased the number of people occupying the social role of research participants, including investigators, analysts and subjects. Simultaneously, addressing scientific questions about autism now involves new research efforts including prospective enriched-risk cohort studies exploring the environmental and genetic causes of autism during pregnancy and early child development. Rather than one-time donations, these studies require extended commitments on the part of all those involved in the research. This article draws on ethnographic observations of research practices and interviews with investigators, study staff and participants to examine the emergent relationships between research and care in this area of autism science. I introduce the notion of 'taking care' to describe the forms of anticipatory labor and mutual extraction involved in longitudinal research. Through tracing three modes of taking care across practices of study design, data collection and participation, I argue that research and care become intimately intertwined and mutually constructed during the research process. These findings reflect how processes of taking and giving are constitutive of research participation for all those engaged in the research enterprise. This article considers the relationships between these practices and new forms of community and sociality related to biomedical science.