Base editing reaches all human embryo cells but triggers unpredictable genetic changes

At the edge of what medicine can imagine, scientists have demonstrated the ability to rewrite the genetic letters of every cell in a human embryo — a threshold once thought unreachable. Yet the study, published in Nature, arrives bearing both a milestone and a caution: the same process that corrects intended mutations also scatters unintended ones, reminding us that precision and consequence are rarely so easily separated. The work of Štěpán Jeřábek and colleagues at Columbia University marks a genuine advance in the long human effort to prevent inherited suffering before birth, while making c