1 INHERITING IDEAS ABOUT INHERITANCE: a study of the explanations to the genetic disorders affecting a large Brazilian family over generations.

The implications of the recent developments of “new Genetics ” have been discussed in the scientific community as well as among educators. Outcome approaches on the public understanding of genetics have shown that the Mendelian laws are not understandable for most people and “common sense ” or lay ideas are still widespread and used to explain hereditary phenomena. The aim of this paper is to consider the genesis of ideas about inheritance and the empirical evidences that support them. Lay explanations are generally considered as the result of cultural background. But how do these ideas arise? Our hypothesis is that ideas about inheritance arise frequently in families with individuals affected by genetic diseases. The proximity of genetic phenomena probably exerts an emotional motivation that induces the elaboration of new ideas based on empirical evidence existing among family members. These ideas may be socially widespread and possibly structure the “common sense” knowledge in a community. In this study, sixty members from a large Brazilian family were interviewed in order to investigate their explanations of the origin of genetic disorders affecting individuals over th