I guess it is! That said, I don't think the 'slippery slope' arguments made in parliament are valid, precisely because this is a very specific kind of genetic modification:

> "But one thing is for sure, once this alteration has taken place, as someone has said, once the gene is out of the bottle, once these procedures that we're asked to authorise today go ahead, there will be no going back for society."

Replacing mitochondria is very different to designing genetic traits, either through careful selection of eggs and embryos, or splicing, and I think that conflating the two is silly.

If laws were introduced that would allow modification of the primary genetic material that debate would be had then. This law will not shoo-in laws that provide for that kind of genetic modification.