The ability to switch out one gene for another in a line of living stem cells has only crossed from science fiction to reality within this decade. As with any new technology, it brings with it both promise -- the hope of fixing disease-causing genes in humans, for example -- as well as questions and safety concerns. Now, scientists have put one of those concerns to rest: using gene-editing techniques on stem cells doesn't increase the overall occurrence of mutations in the cells.

Source: No extra mutations in modified stem cells, study finds