I'm trying to get a handle on mitochondrial replacement techniques and the ethical implications of permitting its use. Currently there are safety concerns, which I'm not going into here. I'm more interested in exploring the other aspects of the debate pertaining to the ethical concerns if this were allowed and if it was safe.

Some background: MRT addresses the problem that some women with mitochondrial DNA (mtDNA) diseases have; essentially it would serve to allow women to have children without passing on these mtDNA diseases. The procedure itself basically involves 3 parties: a man, one woman affected with an mtDNA disease, and a donor woman. Without going into too much detail, suffice to say that the man and the affected woman contribute nuclear DNA, and the donor contributes the mitochondrial DNA. One relevant implication is that the resulting child would have three genetic parents (although the donor contributes only 1% of the child's genetic makeup)

Ethical Issue(s)

The main ethical issue (or at least the one I feel is the most accessible) concerns the child's identity. There is a concern as to what impact this might have on the child's identity, should s/he grow up with the knowledge that s/he has three genetic parents. I think it is pretty safe to assume that this knowledge can have an effect on the child. While there are too many unknowns (for me), if we assume that

1) At least some children will be born as a result of MRT, if it is approved
2) At least some children will be (non-negligibly) adversely affected by having three genetic parents

I think we can get the ball rolling on this particular discussion. I think some parallels can be drawn to children who are adopted/orphans (though there are definitely relevant differences).

Preliminary Thoughts:

There's definitely a tension between the desire of the parents to have a child and the potential implications it has for a child to grow up with the knowledge that s/he has three parents. Part of the answer would have to involve research into the extent of the impact this would have, but even if we do assume that there is some non-negligible adverse effect on the child's future, is that in and of itself grounds to prevent the parents from having the child? Consider: If this is the legitimate reason to ban MRT, should it also be policy to prevent abusive parents from conceiving again? What about couples who do not have the financial means to support a child?

There's also the fact that we already have IVF as an established alternative reproductive technique (ART). This raises issues on both sides of the fence. Since we have already condoned a similar ART, an argument against MRT would have to focus on the differences between IVF and MRT, or it would have to mount an argument against all ART.

On the other hand, since we already have existing means for prospective mothers with mitochondrial diseases to have children, any argument for MRT would have to justify that against IVF/adoption. This would likely entail an argument involving the importance individuals place on having genetically related offspring.

Some other ethical considerations that may be pertinent:
1) Slippery slope into other ethically questionable medical practices (e.g. designer babies, eugenics?)
2) Since MRT involves genetic modification of the germ cell (at least when producing female offspring) there is a potential charge of "playing God".

Final notes: I realize there are vocal antinatalists on this forum, but I hope even the most convicted antinatalist will at least concede that a personal antinatalist moral conviction does not automatically translate into an antinatalist public policy.

Sources:
http://www.nationalacademies.org/hmd/reports/2016/Mitochondrial-Replacement-Techniques (p 6-8, 82, 83)
https://en.wikipedia.org/wiki/Mitochondrial_donation#Technique