External Link - Source: Nature
Of course it was going to happen — and now it has. Last week, an international team reported the use of CRISPR–Cas9 gene-editing techniques to correct a heart-wrenching mutation in human embryos. These attempts worked several times more efficiently than previous ones had, and avoided introducing new genetic errors. Although the embryos were never destined to be used for pregnancies (and have now been destroyed), the work — carried out mainly in the United States — makes it easy to foresee practical applications to genetically alter human embryos.