The authors argue that because cognitive ability is substantially heritable, it is not possible to change it and that remedial education is not worth the effort or cost. This is neither an accurate message from genetics nor a necessary lesson from efforts at remedial education. Heritability estimates are relevant only for the specific environment in which they are measured. Change the environment, and the heritability of traits can change remarkably. Saying a trait has high heritability has never implied that the trait is fated to be.
Height is both genetically determined and dependent on nutrition.
Common conditions in which genetics play a role, such as diabetes or heart disease, can be corrected with insulin or cholesterol-lowering drugs and diet. The disabilities associated with single-gene conditions, such as phenylketonuria or Wilson disease, can be prevented or significantly ameliorated by medical or nutritional therapy. Third, the more scientists learn about human genes the more complexity is revealed. This complexity has become apparent as more genes correlated with human genetic diseases are discovered. We are only beginning to explore the intricate relationship between genes and environment and between individual genes and the rest of the human genome.