Inheritable genetic modification (IGM, also called germline engineering) means changing the genes passed on to future generations. The genetic changes would be made in eggs, sperm or early embryos; modified genes would appear not only in the person who developed from that gamete or embryo, but also in all succeeding generations. IGM has not been tried in humans. It would be by far the most consequential type of genetic modification as it would open the door to irreversibly altering the human species.
Better Mitochondrial Replacement: But Why? by Ricki Lewis, PLOSJune 9th, 2016As long as there are alternative ways to have healthy children, efforts to manipulate mitochondria, unless directed at developing a treatment for patients, should stop.