In this paper we examine new genetics professionals’ accounts of the social context of their work. We analyse accounts given in interview by an ‘elite’ group of scientists and clinicians. Drawing on the work of Gilbert and Mulkay (1984), we consider interviewees’ discourse about knowledge, exploring the way in which they separate science from society through the use of what we have called the ‘micro/macro split’. We then go on to consider the reasons for such a discursive boundary, exploring the interviewees’ wider discourse about expertise and responsibility for the social implications of the new genetics. We argue that interviewees’ discursive boundaries allow them to appeal variously to their objectivity, to dismiss bad science and to characterize the public as ignorant. However, these discursive boundaries are permeable and flexible, and are employed to support the new genetics professionals’ role in guiding education and government policy, whilst at the same time deflecting ultimate responsibility for the use of knowledge on to an abstract and amorphous society. Responsibility is flexibly embraced and abrogated. These flexible discursive boundaries thus promote rather than challenge the cognitive authority of new genetics professionals as they engage in debates about the social implications of their work. We end by challenging the replication of these discursive boundaries, noting some of the implications of such a critique for evaluation of the new genetics.