Journalists, myself included, have called them “three-parent babies” because they are created using DNA from three people. Briefly, the approach typically involves using the DNA from the nuclei of the intended parents’ egg and sperm cells. But it also makes use of mitochondrial DNA (mtDNA)—the DNA found in the energy-producing organelles of a cell—from a third person. The idea is to avoid using the mtDNA from the intended mother, perhaps because it is carrying genetic mutations. That’s why some scientists despise the term “three-parent baby.” Yes, the baby has DNA from three people, but those three can’t all be considered parents, critics argue.