Institute for Health and Aging

In this paper I analyze the concept of heritability as used technically in medical research. I use diabetes as a paradigmatic “common disease” whose heritability is computed with a view to disentangling the relative contributions of “nature” and “nurture”. I show what heritability measures and what it does not, and theorize about the scope of application of this measurement for diabetes-relevant medical research, health care practices, and public health policies. I argue that this analysis applies to heritability studies of comparable diseases and complex phenotypes, concerning which heritability estimates shed little if any light on the nature-nurture question, and provide no information relevant to medical practices and public health policies that we do not already have. I conclude that what is interesting about heritability studies in diabetes and similar human contexts is not what they tell us, or fail to tell us, about the relationship between nature and nurture, but what they show about the social and political nature of the practice of medicine and behavioral sciences.