There are many factors affecting the physical growth of children, which can be broadly categorized into intrinsic and extrinsic factors. 1. Intrinsic factors: Intrinsic factors include heredity, gender, the function of endocrine glands and maternal factors. (1) Heredity: In the process of development, genes determine various hereditary traits, thus there are obvious physical differences among different races, families and individuals. (2) Sex: Sex also has an effect on the rate and characteristics of growth and development, showing differences between boys and girls. Generally girls are smaller in average height and weight before puberty than boys of the same age. (3) Functions of endocrine glands: Endocrine glands play an important role in regulating growth and development, with the pituitary gland, thyroid gland and gonads playing a particularly prominent role. Thyroid hormone, growth hormone, sex hormone, adrenal hormone, insulin-like growth factor-1 (IGF-1), insulin, leptin, etc. are involved in the regulation of growth and development. (4) Maternal factors: The nutritional status of the mother during pregnancy, disease conditions, living environment and other aspects have an important impact on the growth and development of the fetus. 2. Extrinsic factors: Extrinsic factors include nutrition and diseases. (1) Nutrition: Nutrition is the most important influence on growth and development. The younger the age, the greater the influence of nutrition. Adequate and reasonable nutrition is the material basis for children’s growth and development. (2) Disease: All kinds of acute and chronic diseases that cause physiological disorders can have a direct impact on children’s growth and development. When children’s physical growth is abnormal, they should consult a doctor in time to avoid delayed treatment.