To determine whether a child is short, the standard deviation method and the percentile method are generally used in clinical practice. In other words, a child can be diagnosed as short if his or her height is two standard deviations below the height standard of normal children of the same age, sex, region and race, or if his or her height is lower than the third percentile of normal children of the same age, sex, region and race. In daily life, parents can judge whether the child is short by observing the child’s position among children of the same age. If the child is half a head lower than his peers for a long time, has been sitting in the first row of the class, is in the top three in the class, grows less than 5 cm taller every year, and his pants are not too short even after two years, he should be suspected of growth retardation, and should be taken to a regular hospital for examination at a specialist clinic.