Growth disturbances leading to anomalies in a person’s height occur in two forms: too fast and too slow. Growth in children should be checked by regular measurement compared with the growth curve of contemporaries of the same sex. Slow growth can be linked with hereditary factors such as short parents, with malnutrition or chronic illness (such as bronchial asthma or kidney disorders). Genuine dwarfism is less common, and caused by hereditary metabolic disturbances, bone and cartilage conditions or growth hormone deficiency. Infection can cause temporary slowing down of growth, but this is usually quickly made up after recovery. Hereditary factors also play a part in rapid growth – at the onset of puberty, for example, and its associated growth spurt. If puberty begins early, a child can shoot up above his or her contemporaries; this usually happens earlier in girls than in boys, because puberty is later in boys. Growth differences in puberty are quickly made up; the production of more sex hormones at the end of puberty checks the growth spurt. In girls the menarche (beginning of menstruation) is a sign of the end of the growth spurt; body length increases only by a few centimetres after that. Girls who are taller than their contemporaries can often be reassured by the fact that their mother had an early menarche; this is likely also to be the case with the daughter, and suggests that she will ultimately be of normal height. Genuine gigantism is uncommon, and is the result of excessive growth hormone production. Estimation of a child’s ultimate height is aided by testing ‘skeletal age’. A wrist X-ray determines how many growth discs are enclosed in the bones. If the number is greater than is the case with contemporaries, then the skeleton has matured early, and little further growth is to be expected; if skeletal maturity has been delayed, however, then considerable increase in height could still take place. Treatment of abnormal growth depends on the cause; growth hormone excess or deficiency can easily be corrected, as can deficient growth caused by malnutrition or chronic illness. Very tall children whose skeletal maturity suggests high further growth potential may be given sex hormones to accelerate puberty. Production of excess growth hormone in adults, after normal bone growth has ceased, leads to acromelagy.