RecruitingClinical trialHair Biomarkers StudyYoung children aged 0-4 years may be exposed to adverse childhood experiences (ACEs) and/or early life adversity (ELA), which are linked with worse physical and mental health across their lifespan. On the other hand, positive childhood experiences (PCEs) can build resilience and prevent or protect against these detrimental outcomes. Data analyses will assess the interactions of ACEs, PCEs, parenting, and poverty on the early social psychology of childhood and develop objective measures for altered stress regulation using hair cortisol as a chronic stress biomarker.