Reality of "three-parent embryo" news

The mainstream media buzzed yesterday with reports that scientists created a human embryo from three parents, a man and two women. According to the scientific journal Nature's online news site, those experiments at the University of Newcastle upon Tyne have been blown a bit out of proportion. Even still, their success so far does boggle the mind. From Nature News:
The experiments aim to replace genetically damaged structures called mitochondria, found in a woman's egg cells, with healthy mitochondria from unrelated eggs. The experiment has been mooted as a way to help women with diseased mitochondria have healthy babies.

Their work so far has reportedly created ten viable embryos containing genetic material from multiple 'parents'. But these resulted from transplants of DNA between embryos, rather than into a healthy egg as will be needed in future; it is not clear that the procedure will work in normally fertilized eggs.

The team says the progress confirms their hope that nuclear DNA can be taken out of embryos while leaving most, but not all, of the mitochondria behind – a step that will be needed in future for the procedure...

So far, (neurogeneticist Patrick Chinnery) Chinnery said, the Newcastle team has only exchanged the nuclear DNA of embryos that have failed fertility treatments. In other words, it has transplanted nuclear DNA from one failed embryo to another – not from one embryo into a healthy donor egg, as has been widely reported. These failed embryos contain abnormal doses of nuclear DNA...

"There are still a number of scientific issues we've got to resolve, in terms of efficiency, and in terms of whether we can do this in eggs rather than in other embryos," Chinnery said.