Certain issues involving science are widely regarded as ethical or social – the appropriate moral and medical responses to abnormal fetuses, for example. The “concept of abnormality” itself is not usually one of these social or ethical issues. It is assumed that science tells us what is normal or abnormal, diseased or healthy, and that the social and moral issues begin where the science leaves off.

For many purposes, such an understanding of science is appropriate. In this chapter, however, I would like to challenge the “givenness” of the categories of normality, health, and disease. By understanding the differences among various biological theories and the distinguishing features of their respective goals and approaches to explanation, we can analyze the way in which scientifically and socially controversial views are sometimes hidden inside apparently pure scientific judgments.

I am not suggesting that the misleading nature of some of the scientific conclusions I discuss implies some unsavory intention on the part of the scientists involved. On the contrary, my point is that there are sincere scientists working among different theories and subfields, each with their own standards of explanation and evidence. The diversity of theories and models involved in implementing the Human Genome Project provides a unique challenge both to the producers and the consumers of the DNA-sequencing information. I contend that the problems arising from this diversity have not been recognized or addressed.