Jennifer Doudna co-invented the CRISPR system which can help to cure genetic disease by making changes to the DNA in cells and editing genomes. This system was first discovered by scientists when examining how bacteria fight viral infections. Scientists realized that using this system they could change, with incredible precision, parts of the DNA of cells and can be used in many different organisms, humans included, to cure diseases. The CRISPR system acts like a genetic vaccination in cells correcting mutations that cause disease. Jennifer Doudna also addresses the ethical issue of human genetic engineering.