 Child development consists of several interdependent domains of sensory-motor, cognitive-language, and social-emotional function. Childrens development is affected by psychosocial and biological factors through changes in brain structure and function, and behavioral changes. Experiences in the first few years of life are of particular importance because vital development occurs in all the domains during this period, and the interaction between early environments and genetics influences this development and human behavior. The brain growth occurs rapidly through neurogenesis, axonal and dendritic proliferation, synaptogenesis, cell death, synaptic pruning, myelination, and gliogenesis. Brain development can be modified by the quality of the environment. Independent animal research suggests that early under nutrition, iron-deficiency, environmental toxins, stress, and poor stimulation and social interaction can affect brain structure and function. In both humans and animals, variations in the quality of maternal care, a part of home environment, can yield changes in stress reactivity, anxiety, and memory function in the offspring. In later childhood the affected children will subsequently have lower levels of cognition and education. It is mentionable that remarkable recovery is often possible with early intervention through more nurturing environment with adequate stimulation, despite the vulnerability of the brain to early insult. 