The ability to permanently alter or repair the human genome has been the subject of a number of science fiction films, but with the recent
advent of several customisable sequence-specific endonuclease technologies, genome engineering looks set to become a clinical reality in
the near future. This article discusses recent advancements in the technology called ‘clustered regularly interspaced palindromic repeat
(CRISPR)-associated genes’ (CRISPR-Cas), the potential of CRISPR-Cas to revolutionise molecular medicine, and the ethical and regulatory
hurdles facing its application.