Science and security policy are increasingly overlapping because of concerns that legitimate research might be misapplied to develop biological weapons. This has led to an expansion of security policy to cover broad areas of research and scientific practice, including funding, publishing, peer-review, employment, materials transfer, post-graduate teaching and academics’ ability to design and perform experiments and disseminate research. Such changes raise policy concerns because many of the technologies used to produce biological weapons are ‘dual use’ and have legitimate peaceful applications. As a result, attempts to control their generation, diffusion or application can have unintended impacts on socially beneficial applications. This paper explores recent changes in the governance of science and technology and contributes to future policy making by assessing the relative merits of understanding the development of dual use policy in terms of either technology transfer or technology convergence.