This is misleading and totally exasperating to anyone who knows a little of the science. The mitchochondrion is a vital part of our cellular metabolism and it has its own genes, albeit very few of them. It is friendly little parasite. The mitochondrion is the cell’s powerhouse and it derives from an ancient piece of cellular fusion 1.5 billion years ago when life consisted only of single-celled organisms. One cell swallowed another and put its machinery to work. The mitochondrion was once a bacteria-like entity but in higher animals it has lost almost all its genes except those that carry out its vital energetic functions. It does not have “people” genes, only a few relics of its ancient bacterial genes. It is a kind of battery, if you like. The biochemical functions of the mitochondrion are common to every form of multi-cellular life – it is low-level chemical plumbing.
We accept heart and other transplants as routine these days. If you‘re happy to take a dynamo from another person, why not start a baby with a battery that works? A baby resulting from mitochondrial transfer is A Man a Woman and Battery Pack or, if you prefer A Man a Woman and a 1.5 Billion Year Old Piece of Cellular Metabolism. Not a Three-Parent Baby.