Some countries have introduced a requirement for genetic impact assessments prior to granting permission for the import of new exotic livestock breeds. However, the merits of such a system are not universally accepted. During February 2007 a discussion on the subject took place on FAO's Domestic Animal Diversity Network (DAD-Net) electronic forum. This paper presents a description of how the discussion developed, and a summary of the issues raised. Arguments both for and against requiring impact assessments were put forward. Those opposing such measures focused on the risks of limiting access to animal genetic resources (AnGR), and questioned the benefits of government interference. Practical constraints to implementation and enforcement were also noted. Counter arguments pointed to the potential for avoiding the loss of valuable AnGR, and stressed governments' responsibilities to intervene where necessary to promote sustainable development, to defend the interests of the poor, or to protect national heritage. The debate ranged more widely — encompassing the respective roles of local and exotic AnGR in different regions of the world and in different production systems.