CRISPR is an adaptive immune system found in a bacterium and archaea, which is now used as a tool for human genome modification. And technology is developing fast. This episode is about what CRISPR is, how it can be used, and what ethical dilemmas are involved. And how CRISPR is more than a tool for genetic engineering, it is a tool for understanding the interaction between the bacteria and viruses in our gut, our immune system and maybe even our behavior. The potential of science is full of hopes and dreams, dangers and fears.A Science and Cocktails production funded by The Novo Nordisk FoundationContributing scientists: Roger Antony Garrett, Professor emeritus in Functional Genomics at University of Copenhagen. Guillermo Montoya, Research director and Professor at the Novo Nordisk Foundation Center for Protein Research at University of Copenhagen. Xu Peng, Associate Professor in Functional Genomics at University of Copenhagen. Shiraz Shah, Senior Scientist at Gentofte Hospital.Journalist, Sound designer and producer: Sofie HjorthMusic composer: Hjalte Bested MøllerFor more cool science visit http://www.scienceandcocktails.org