In children with mental retardation, development is altered so that adaptive and cognitive skills are significantly deficient. Causes of mental retardation are varied and include newborn trauma, infectious diseases, chromosomal abnormalities, metabolic disorders, and environmental toxins. In many cases, however, the cause of mental retardation remains unknown. Most affected children have mild retardation and are able to achieve economic and social independence as adults. Early identification by the pediatrician of a developmental delay is important to ensure appropriate treatment and to enable the child to develop all of his or her capabilities.