[heero_yuy]

The (defective) mitochondria are only passed on through the female parent. Who could argue with preventing the resulting debilitating illness and early death of a child so affected?

But many see this as a step along the road of genetic engineering or selection by genotype. If it is to prevent serious illnesses that have no other cure, I'm thinking cystic fibrosis and similar here, should we really not embrace this?

But how far to go? Give everybody 20/20 vision?

Sooner or later we'll be able to select or even engineer for relatively trivial things such as eye colour, hair colour etc. No matter what the regulators say money will allow it to happen.