Most of the genetic material in our cells is contained in the chromosomes which we inherit as a mixture from our mothers and fathers, but not all of it. A small amount of DNA is found in the mitochondria, the little structures in our cells that act like batteries. The only way to prevent the transmission of the genetic diseases of the mitochondria to date in couples who wants their own genetic children has been through the use of donor egg IVF. The problem is with donor egg is that the baby receives no genetic material from the the mother, and that only way around that problem would be to move the nucleus (which contains mom's genetic material) from the mother's egg into a donor egg. That process is called nuclear transfer and was banned by the US government because it involves cloning technologies. Now the FDA is considering lifting the ban to allow research into IVF with nuclear transfer for mitochondrial diseases. If successful, this would create babies with 3 genetic parents for the first time, a genetic mother, a genetic father and a mitochondrial mother. Quite a bit to ponder.