WOWWW! Just saw a news item on PBS. Apparently scientist have succeeded in replacing a defective gene in a human embryo with a CRISPR substitute. In this case it was a repair of a genetic heart defect. According to the spokes-person, there are limits to such procedures and this was just one successful laboratory experiment. She explained that the main problem is in finding the exact location and correct repair of the defective gene. She further explained that a clinical trial would involve a host of incidental problems and it would have to be a long term trial as implanting an embryo would add the health of the surrogate mother into the equation and if brought to term, the subject would have to be studied during its lifetime, for any possible unexpected side effects. While there are some moral concerns about genetic engineering, the spokesperson said the research was focused on repairing genetic defects and if this then could be passed on to offspring, effectively doing away with pre-existing conditions, which might have a beneficial impact on health insurance and future medical treatment of offspring, if the repaired gene was passed on. She ruled out the addition of extra DNA for specific extra abilities, as that would almost certainly affect other DNA codings, and produce unexpected interactions with other parts of the DNA. Nevertheless, this was the first time that this repair of a single code had been successfully performed. But she qualified that clinical testing was still a long time off, before they would even try to take the next step. All the same, it is a remarkable scientific development.