To summarise; the genetics of growth includes the genetics of growth regulation, for growth is tightly controlled, as evidenced by catch-up growth and the increasing similarity of MZ pairs as a result of growth in the first year. Tempo of growth is under genetical control but quite separately from size. Its heritability is not very different from the heritability of size. Genetic similarity between parents and offspring can be allowed for in the clinic either by using parent-allowed-for regression-type standards for height, at ages 2.0 to 9.0, or by comparing the predicted adult height of the given child with the target range of adult heights characterising the offspring of the particular parents.