The genetic revolution is taking the world by storm. Reports of the latest genetic breakthroughs and their projected impact are inescapable. For people with cancer, gene therapy holds out great promise for their treatment in the future. But our uncertain understanding of genes as treatments for disease and the lack of data about the wider effects of gene therapy means that, when nurses are involved, their responsibilities must be clear. The main author of this article is a research nurse involved in clinical trials of genetic modification of live cancer cells. She describes the many aspects of her role and discusses how the introduction of a novel and often controversial treatment has affected her work.