Scientists for the first time have successfully edited genes in human embryos to repair a common and serious disease-causing mutation, producing apparently healthy embryos, according to a study published on Wednesday. From a report: Now, an international team of scientists reports they have, for the first time, figured out a way to successfully edit the DNA in human embryos -- without introducing the harmful mutations that were a problem in previous attempts elsewhere. "It's a pretty exciting piece of science," says George Daley, dean of the Harvard Medical School, who was not involved in the research. "It's a technical tour-de-force. It's really remarkable." The research is ultimately aimed at helping families plagued by genetic diseases. The new experiment used a powerful new gene-editing technique to correct a genetic defect behind a heart disorder that can cause seemingly healthy young people to suddenly die from heart failure. The experiment corrected the defect in nearly two-thirds of several dozen embryos, without causing potentially dangerous mutations elsewhere in the DNA. None of the embryos were used to try to create a baby. But if future experiments confirm the techniques are safe and effective, the scientists say the same approach could be used to prevent a long list of inheritable diseases.