The safety of CRISPR-Cas9 gene editing is being debated

A GREAT deal rides on the accuracy of the gene-editing tool known as CRISPR-Cas9. Since its discovery in 2012 it has become popular for tinkering with genomes of all kinds, thanks to its ability to make editing cheap and easy. Firms such as CRISPR Therapeutics, Intellia Therapeutics and Editas Medicine have been built on the idea that it could be used to develop treatments for human diseases. Editas, based in Cambridge, Massachusetts, announced this year that it would work on five new human medi...