*This paper is derived from a research project, ELSI Research and the Construction of Legitimate Expertise, funded by a Social Science and Humanities Research Council standard operating grant for which the authors are grateful. Earlier versions of this paper have been presented at the Sociology of Bioethics Mini-Conference at the 2005 Eastern Sociological Society meeting in Washington D.C., the 2005 Society for Social Studies of Science (4S) conference in Pasadena, and the Genes and Society session at the 2005 Canadian Sociology and Anthropology Association in London, Ontario. We are grateful to the organizers and the participants for their input and suggestions. In addition, the authors wish to thank the anonymous reviewers for their very helpful comments. This manuscript was first submitted in January 2006 and accepted in June 2006. Contact: firstname.lastname@example.org; email@example.com.