Mitochondrial replacement IVF does one simple thing: replaced a single strand of the mother's DNA with third-party mitochondria from a healthy egg donor, as mitochondrial DNA is passed down from the maternal line.
The technique, known as mitochondrial replacement, is designed to produce babies with healthy mitochondria, a change in their genetic structure that would be passed on through the generations.
It would be unscientific to argue that because things turned out fine on that occasion, they will inevitably do so for mitochondrial replacement.
Rather, mitochondrial replacement therapy, which combines DNA from three adults, will be used for in-vitro fertilization only in women who carry the mitochondrial mutation.
Lehigh University's Dena Davis, a bioethics professor specializing in religion and law, notes that debates over mitochondrial replacement are often the result of confusion.
As one of the versions of mitochondrial replacement involves the destruction of embryos, it was bound to fall foul of Catholic doctrine.
As was the case with mitochondrial replacement IVF, the UK gave birth to traditional IVF well before the US embraced the technology.
I strongly suspect that, beneath many of the arguments about the safety and legality of mitochondrial replacement lies an instinctive repugnance that is beyond reason's power to articulate.
So why isn't three-person IVF available in the US? Mitochondrial replacement therapy was first performed successfully in 1996, in the United States, but there remains vocal concern (and confusion) as to whether mitochondrial replacement IVF might lead to widespread genetic engineering.
In 2001, the FDA effectively banned an assisted reproduction procedure similar to mitochondrial replacement IVF, cytoplasmic transfer, in which donor egg cytoplasm is injected into an egg with mutated mitochondria.
This week, the House of Lords voted 280 to 48 to approve 'three-person in vitro fertilization' (IVF), also known as mitochondrial replacement therapy, which combines the DNA from three adults.
