Vulnerability in research: a developmental perspective on research risk. 
Assessing potential risks to children who participate in developmental research is a challenging task because children are a heterogeneous population, varying in developmental competencies and in background characteristics.  This essay offers a developmental perspective on research risk, emphasizing that children's vulnerability to research risk changes in complex ways: some risks decrease with increasing age, some increase as the child matures, others change in a curvilinear fashion, while some remain essentially stable with development.  Because vulnerability in research does not simply decline linearly with age, assessments of research risk must entail multidimensional considerations that vary over developmental time.  In a similar manner, individual characteristics of children at any age (e.g., maltreatment, at-risk status, etc.)  may also heighten their vulnerability to certain risks which require special consideration by researchers.  Finally, this discussion of developmental vulnerability and the principles underlying research ethics suggests that in addition to the conventional risk/benefit analysis, researchers are in an optimal position to establish and maintain standards of decent treatment of children in research that safeguard their rights as research participants.  Suggestions for fostering this process in the research community are outlined.