Dr. Megan Gunnar from the University of Minnesota reviews key findings from behavioural and neuroscience research on early development that explains how early adversity gets under the skin to influence developmental outcomes. She focuses on the biology of stress and its role in mediating the impact of early adversity. The presence and availability of supportive, consistent adult caregivers is critical to whether or not adverse events trigger toxic stress responses in the child. Dr. Gunnar reviews evidence of the power of supportive relationships in regulating stress and preventing toxic stress in infants and children and the vulnerability of the child to toxic stress when those relationships are not available or dysfunctional.