The deleterious effects of institutionalized care on the health and growth and development of children have been described. Early studies have shown that the effects of institutionalized care on a child's growth and development may not be fully reversible. The exact mechanism through which these early stresses affect bio-behavioral outcomes has yet to be determined. A likely mechanism in which environmental influences could regulate both biological and psychosocial development may be through the hypothalamic pituitary adrenal axis (HPA). Recent advances in the area of brain research have enriched our understanding of the importance of early life experiences on physical, cognitive, developmental, mental and behavioral health outcomes. Children adopted from orphanages in countries as diverse as the former Soviet Union and Guatemala provide an opportunity to learn more about the effect of deprivation on neuro-endocrine function, physical growth, and developmental outcomes, including cognitive and behavioral measures.