The technique is still far from being available to parents. Editing human germ cells and embryos is illegal in many countries and is widely considered unethical4, 5. In recent weeks, several research groups have called for a moratorium on such work until guidelines can be developed to delineate legally and ethically acceptable research or clinical applications. Izpisua Belmonte and Ocampo are waiting for approval from ethics boards before applying their technique to human cells.