For a woman with faulty mitochondria, scientists take only the healthy genetic material from her egg or embryo. They then transfer that into a donor egg or embryo that still has its healthy mitochondria but has had the rest of its key DNA removed. The fertilized embryo is then transferred into the womb of the mother.
Some groups oppose artificial reproduction techniques and believe the destruction of eggs or embryos to be immoral. British tabloids jumped on the procedure when it was first announced in 2008 and labeled it the creation of a three-parent baby -- the mother, the donor and the father -- a charge scientists claim is inaccurate because the amount of DNA from the donor egg is insignificant.
