Dwarfism, or restricted growth, is usually a genetic condition resulting in short stature of a child with parents of normal height. It may also be developed as a result of organic disease or determined by environmental factors in the case of a genetically susceptible individual. Only where dwarf height occurs in defined racial populations can the condition be considered hereditary.
Microsomia has three forms: in the first one there is only a deficiency in stature; in the second one additional serious hypogenesis of the skeleton except for a large skull is present; and in the third one includes a combination of infantilism and premature senility. Racial dwarfism occurs in some groups whose physiological bodily functions are otherwise quite normal. Sub-normal height creates a multitude of special problems for such individuals in relating to others and in using facilities designed for those of average height.
The normal height of adult men has been arbitrarily set at 150 cm, and on this basis dwarf populations exist in Central Africa, the Andaman Islands, Philippines, and New Guinea. The pygmies of Central Africa have heights down to 120 cm.