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Three-Parent In Vitro Fertilization

By Promi Chakraborty


With the onslaught of new breakthroughs in research, the answer to the question “where do babies come from?” has increasingly become more nuanced. A good example of this is a procedure that has been legalized in only the United Kingdom and Australia called three-parent in vitro fertilization (IVF), also known as mitochondrial donation or transfer, developed with the goal of preventing mitochondrial diseases from being passed from mother to child. Mitochondria are the only other organelles that contain DNA other than the nucleus, DNA that is only inherited from the mother to all her children. Even though mitochondrial DNA makes up only around 1% of inherited genetic material, it is still vulnerable to mutations that cause debilitating and sometimes fatal diseases in children.


There are a few different techniques in which healthy mitochondria is donated in three-parent IVF, but the two of which have become the most significant are maternal spindle transfer and pronuclear transfer. In maternal spindle transfer, the nucleus is removed from the donor’s egg, leaving an empty egg behind with fully functioning mitochondria. Then, the nucleus from the potential mother’s egg, which excludes the damaged mitochondrial DNA found in the cytoplasm, is taken and inserted into the empty egg of the donor. After this egg is fertilized with the potential father’s sperm, it is implanted in the mother’s womb, and normal gestation ensues. In pronuclear transfer, both the mother’s egg and the donor’s egg are fertilized by the father, allowing the formation of two zygotes. The nuclear material, or pronuclei, from the zygote created by the donor and the father is discarded, and the pronuclei of the zygote formed by the parents is taken and implanted into empty zygote of the donor and father, where there are healthy mitochondria.


There are both proponents and opponents of three-parent IVF. Proponents, many of which are from families with individuals who have mitochondrial disease, say that this method of genetic engineering would allow women with mutated mitochondria to have healthy children with very minimal genetic material from a “third parent,” and that the interests of parents with concerns over passing on mitochondrial defects should be prioritized over the law. However, those who view this development with consternation bring up potential issues that this technology could give rise to.


One such issue is the lack of profound research surrounding this procedure– since researchers are still in the dark from certain facets of this type of genetic engineering, there is no guarantee that mitochondrial donation is completely safe. For instance, scientists suspect that there needs to be similarities between the mitochondrial genome of the mother and that of the donor in order to avoid failure of or problems with the replacement. Another issue that was raised was a concern over whether some of the damaged mitochondria from the mother would remain stuck to the nucleus when it would be transferred. More research needs to be done before these concerns can be settled, which is something that makes many hesitant to support this technique.


While mitochondrial DNA has little impact on a child’s personality and appearance, which are mainly coded by the nuclear DNA from the parents, another key concern that has been raised over three-parent IVF is whether being born to “three parents” would lead to challenges with identity for the child in the future. Many opponents raise the argument that while parental nuclear DNA would still dominate the child’s genome, a person’s identity encompasses much more than their genes and that a third party contributing to the person’s conception would have a definite impact on how the individual’s narrative evolves. Furthermore, a person born without mitochondrial disease would end up projecting a completely different character and nature, raising questions among the public about whether this alteration in identity would be ethically permissible.


Beyond uncertainties within the private sphere of the self, points have been raised about the broader social impact that mitochondrial donation can have. People have argued that since there is still so much not known about this form of reproduction, it could have unsolicited and irreversible consequences for genetic heritage as a whole, which may result in dangerous effects on humanity. There are also pious individuals who are against three-parent IVF due to religious reasons, as it is not completely certain whether this technique protects the sanctity of creating life. Finally, one of the two major processes of three-parent IVF, specifically pronuclear transfer, is being more heavily criticized because this certain technique involves the destruction of at least two embryos.


While research is rapidly progressing, it could be likely that uncovering more details about three-parent IVF will merely fuel the debate over the already present ethical and societal issues surrounding it in the coming future.




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