Simon and Rach take a deep dive into gene drives this week, examining the work being done to make island conservation less lethal to the inhabitants it is supposed to be protecting. We consider how CRISPR technology might be able to help with this, how it works and what the unintended consequences of using it might be. Our theme music was written and performed by Laurence Owen. Graphics by Theo Weedon, web design by Ian Bridgeman, support from the Wellcome Trust. The producer is Rachel Wheeley. More information about the series is at www.leveluphuman.com and you can support us at www.patreon.com/leveluphuman