Synthetic biology is based on the idea of constructing living organisms ‘from scratch’ to serve human needs and economic interests. So far, scientists have been unable to achieve these goals – except to a very small extent. However, a basic tool used in ‘SynBio’ – the synthesis of DNA and RNA – has become an important tool in many potential usages, including the production of vaccines, the synthesis of whole genomes from viruses, bacteria and yeast. CRISPR/Cas gene scissors are guided by synthetic RNA to the target site. In future, fields might even be sprayed with pesticides containing RNA. These new pesticides are associated with many different risks that are very difficult to assess.