Now, an article in Science validates the safety point I made. It turns out, the process has not been studied in humans past the 10-cell embryo stage, nor in monkeys into adulthood. But studies with mice and other organisms show significant health problems for males. From the article:
Studies on model organisms, ranging from mice to fruit flies, indicate that MR [mitochondrial replacement] can profoundly change the expression profiles of nuclear genes and affect a range of important traits such individual development, cognitive behavior, and key health parameters. These studies also suggest that males of reproductive age are particularly sensitive to MR-induced effects.
Even if one doesn’t think–as I do–that there are intrinsic moral problems with the creation of 3-parent embryos, allowing such children to be created in the face of such known risks would be unethical human experimentation.
Some might say, Oh well, just use sex selection before implantation. That’s also unethical to me, but even if one doesn’t think so, note this:
Altered respiratory metabolism and reduced performance, learning, and exploratory capacity in males were reported when mitochondrial-nuclear genomic interactions were experimentally mismatched. Females were not tested in those studies.
The authors suggest further studies. But then, they conclude:
Some families who are predicted to be, or who have previously conceived offspring that were, severely afflicted by mtDNA diseases are more likely to be prepared to take the risk. Others whose children are expected to suffer less detrimental symptoms, cognition problems or infertility, may wish to wait for further empirical clarification of the risks involved.
No. Our intensifying focus on the deep yearning of want-to-be parents in this field is misplaced. It leads to desperate, and ever-more intricate manipulations that create a crescendo of morally contentious actions and outcomes.
It causes great pain for would-be mothers to choose not to become pregnant because of a genetic health condition. Yet, all is not lost. Parentless children are waiting desperately to be welcomed into good and loving homes.