In May 2023, with the approval of the United Kingdom’s Human Fertilisation and Embryology Authority, the first UK baby was born using a “three-parent embryo” technique, better known as mitochondrial replacement therapy (MRT). The process, which has been hailed as a reparative therapy, involves the transfer of both nuclear and mitochondrial DNA. Nuclear DNA is responsible for our unique personality traits and physical characteristics, while mitochondrial DNA is responsible for cellular energy production. 

MRT aims to prevent the transfer of mitochondrial disorders to the offspring of women suffering from mitochondrial disease, specifically women because children inherit their mitochondrial DNA, or mtDNA, solely from their mothers. Mitochondrial disorders, affecting approximately 1 in 5,000 births in the U.S., can cause devastating effects on organ function and leads to premature death

MRT does not provide a cure, but rather creates new persons who otherwise wouldn’t exist as opposed to treating existing ones. Thus, as defenders of children’s rights, we must ask the question of whether MRT is truly “therapeutic,” or if it amounts to eugenic experimentation on early human beings. Is it ethical to design children in the name of “therapy?” 

Maternal Spindle Transfer

There are two main types of MRT: Maternal Spindle Transfer (MST) and Pronuclear Transfer (PNT). Both MST and PNT are problematic, in that they experiment on unique embryonic babies with the intent to realize only one healthy, live birth. As bioethicist Dr. Maureen Condic states, “Sperm/egg fusion sets off a cascade of molecular events that control events that are going to take place weeks, or even months later in human development. These events are absolutely not required for cellular life – cells don’t need to do them to survive, but rather, they only make sense in the context of a developmental sequence that’s produced by an organism.” In other words, an embryo isn’t simply a clump of cells. In typical cellular behavior, cells will produce more of themselves through natural cellular cloning, but embryos undergo a “self-directed, organized, pattern of development to generate a fetus, and it doesn’t function as a single cell, or even as a group of cells – it functions as an organism.” Human beings create human organisms, better known as human beings. Therefore, upon sperm/egg fusion, a new cell (commonly referred to as a zygote or early embryo), with its own unique composition and behavior comes into existence. A zygote isn’t simply a new cell on its way to becoming a human being. This zygote possesses all of the attributes of a complete, although immature, human being, and therefore has the right to life from the moment of fertilization. 

Maternal Spindle Transfer begins with a harvested egg from the “intended mother,” that is, the woman suffering with a mitochondrial disorder and who will raise the child. A healthy “donor” egg is then procured. The “spindles,” or clusters of chromosomes containing the genetic material from both women are removed from the eggs, and the spindle from the intended mother is placed into the donor egg. The egg is then fertilized with sperm from the intended father and a new human being, with DNA from three persons (a chromosomal mother, an egg mother, and a sperm father), is created. This human will have a condition called “heteroplasmy,” meaning that it contains a mix of both healthy and unhealthy mitochondria, because it is beyond our ability to entirely remove the DNA from the intended mother’s egg without a few mitochondria tagging along. Heteroplasmy is only one natural consequence of trying to distort human genetics at the most fundamental level.


There are numerous risks to children inherent to the process of MST. Producing children via In Vitro Fertilization alone puts children at an increased risk of health problems. There is also the risk of damage to the maternal spindle during transfer, resulting in genetic abnormalities. Further, the donor egg could suffer damage through the removal of its spindle, resulting in embryonic death or abnormal fetal development. These risk factors will result in a large number of tiny humans who are subsequently eliminated either by a natural death or termination, all in the hopes of creating at least one healthy child. Then, due to heteroplasmy, the bad mitochondria can get the upper hand and revert the healthy mitochondria, causing the mitochondrial disease the procedure was intended to eliminate to persist.

Prenatal testing can occur around 12 weeks in order to determine whether reversion has occurred, and if so, this may lead to selective reduction of children found positive for mitochondrial disorder. Because this disease is exclusive to females, another consequence of preventing mitochondrial disorder may include sex-selection pressures, which may occur as part of the preimplantation genetic screening or selective reduction process. Intended parents may choose to select only boys through the IVF process to prevent any possible risks incurred through MRT, as “limiting MRT to male embryos takes away the fear related to the transmission of mtDNA diseases as well as unexpected side effects of MRT to future generations, since mtDNA inheritance is exclusively maternal.” This technology requires a whole lot of collateral damage to satisfy an adult’s desire to have a child.

MRT may not actually be necessary in the first place. For example, if a woman has severe mitochondrial disease, she won’t survive to reproductive maturity. Further, if a woman isn’t strongly affected, then her disease can usually be managed without serious risk. If the mother isn’t strongly affected but ends up having a child with severe mitochondrial disease, it isn’t a certainty that her second child will have the disease. Due to heteroplasmy, each individual egg cell inherits a random mix of both good and bad mitochondria. While some of the spectrum of egg cells will have bad mitochondria and some have good, most of them will look like the mother. Should we really take the risk of manipulating human beings and sacrificing the lives of untold persons for something that may not be an issue for future offspring?

Lastly, MRT introduces a permanent, heritable alteration in the human species due to germline manipulation, as these changes are passed onto future offspring. According to Japanese researchers, “Germ line modifications would inevitably affect the entire body, including transmission of genetic traits to the next generation, inducing heritable changes. Furthermore, drastic mitochondrial genetic drifts occur when the mtDNA goes through the female germ line…there is a possibility of disease manifestation in future generations of MRT, which will probably become evident after two generations.” 

While MRT doesn’t involve the manipulation of a specific gene since it doesn’t alter the egg’s pronuclear material, it’s possible that this man-made modification can still impact the way genes function in unpredictable ways. The assumption is that mitochondria don’t possess an individualized nature and simply work like batteries that can be swapped with any other mitochondria. This leap of faith informs the belief that modifications to cells, genetic or otherwise, aren’t capable of producing heritable changes. But in reality, as neurobiologist Dr. Greg Pike states,”…Genes operate in concert with one another as well as with the cellular, organismic, and external environment. MRT, contrary to what the term implies, involves replacement of all the cellular ‘machinery’ as well, that is, everything but the nucleus.” 

The truth is, we simply don’t know what will result from experimenting with the ‘machinery’ of cells and whether it will cause permanent germline alteration in future generations, but we are foolish to assume that altering one component of a ‘machine’ doesn’t ultimately affect the functioning of the entire machine, no matter how seemingly insignificant that part is. 

Pronuclear Transfer

Much like MST, Pronuclear Transfer (PNT) starts with an egg cell from the intended mother and a donor. The eggs are both fertilized with sperm, creating two distinct embryonic human beings. The nucleus from the first embryo is then transferred to the donor embryo containing the healthy mitochondria, creating an embryo with nuclear material from the intended parents and donor mitochondria. This is incorrectly named as “mitochondrial replacement,” when it is actually a transfer of chromosomes because the nucleus of the embryo, not the mitochondria, is transferred.

PNT is actually a form of destructive, eugenic cloning. In the cloning process, an egg is stripped of its genetic material and a somatic body cell is inserted into the empty egg. A zygote with nuclear information identical to what is present in the somatic cell donor is formed. In PNT, destruction of human beings occurs when the pro-nuclei are removed. The process is eugenic because we’re making judgments about who should have the right to keep living and whether they should be allowed to reproduce, as, according to Dr. Condic, “…we’re destroying the unfit human in order to produce a fit one, using another human who isn’t even given the status of human.” The nuclear transfer aspect of PNT is cloning, because an embryo with the same genetic material is being created twice through the destruction of the first embryo. This is no different than involuntary organ harvest, one human sacrificed in order for another to live.  


While PNT shares the risk factors with MST, it introduces new risks pertaining to the cloning process. The outcome in the animal cloning process has been fraught with adverse effects such as miscarriages, genetic malformations, cancers, and shortened lifespans. Cloned animals are often born larger than average size with abnormally large major organs. These improperly sized organs can cause circulation, breathing, and other problems with bodily function such as immune system failure. In addition to concerns related to cloning, a study in mice has shown that those who had nuclear and mitochondrial DNA from different mothers aged faster than normal mice, which resulted in significant longevity differences. This incompatibility among mitochondrial and nuclear genomes is likely to occur in humans as well, because When a MRT is performed, [the] uniparental inheritance mechanism is broken: the nDNA is located in a completely new environment, with alien mitochondrial genes and with the risk of generating incompatibilities derived from these new nDNA–mtDNA associations.”

If we are concerned with protecting the rights of children, we must oppose any scientific experimentation that treats them as disposable, alterable test subjects; as materials to be manipulated because we believe we know what’s “best.”

Three-person parenthood

Generally the “three-parent” assessment is derided as a misnomer, and that “egg donors should not be considered third parents as the mitochondrial genome only accounts for a small component of the overall genome…and that the prospective children would largely have the genetics of the intending parents.” With MRT, 99.8% of the child’s DNA comes from the mother and father. About 37 genes, less than 1%, come from the donor via mitochondrial donation. 

According to the Human Fertilisation and Embryology Authority, women who donate their eggs or embryos for MRT won’t be the genetic parent of the created child, and the donors remain anonymous. However, the child, at the age of 16, can access their donor’s personal and family medical history, their personal description, and any other information they have agreed to share. If there isn’t an innate understanding of the importance of parent/child genetic connection, why would access to this information be considered important? 

There is a push for MRT to be expanded beyond a so-called “therapy” to cure medical issues and used by lesbian couples to create children genetically related to two mothers. In this argument, 37 genes appears to be enough to constitute genetic relatedness. Queer-rights activist Rohin Bhatt states, “…giving birth to biological children is perhaps the most basic of the procreative rights…any liberal society that only provides heterosexual couples with a means to meet their reproductive needs has a skewed view of equality…homosexual couples have already limited reproductive autonomy that deprives them of their reproductive freedom…Ensuring lesbian mothers have access to mitochondrial replacement therapy will ensure that the rights of both mothers are equal and that the rights of the mother who gives the nuclear DNA do not supersede the rights of the other mother on mere account of genetic similarity.” 

Genetics Matter- When Adults Want It To

This is contradictory to the idea that mitochondrial DNA contributions are too minute of a percentage to justify genetic connection. The pressure to allow homosexual couples to adopt children is derived from the desire to prove that the genetic link is unimportant in parenting, yet, the push to give same-sex couples access to these technologies reveals the importance of a genetic connection. This mindset, much like gamete donation, illustrates that genetics only matter to adults when it suits their desires. 

Which is it?

Love makes a family” is an often touted slogan of the LGBT community in an attempt to justify the “right” of same-sex couples to create families. Our societal conversation is dominated by this mantra, from our daily conversations, to books for children, to websites full of stories of LGBT families emphasizing that “DNA doesn’t make a family, love does,” to various fertility specialists stating that love and attention are more important for children than having a mother and a father.

Yet this technology makes clear that biology does indeed matter when the adults want it to, otherwise they would simply use the egg of an unrelated adult, rather than employing an experimental treatment so they can have some shred of genetic connection with their child.

Similarly, same-sex couples will also choose egg/sperm donors based on physical descriptions, personality, ethnicity, education, or other characteristics that closely match the non-genetic partner’s family. Some male partners will use their sisters/ sister-in-laws as egg donors in order to have children who match both genetic trees and are more likely to have physical characteristics and personality traits of both men, or use sperm from both men with the hopes of having one child biologically related to each man like David Burtka and Neil Patrick Harris achieved. Same-sex female couples, other than picking sperm donors to match their partners’ characteristics, will do what is called “reciprocal IVF,” which is where one partner will donate the egg and the other will carry the child and vice versa if they decide to create a second child. This allows both partners to experience both pregnancy and a genetic connection to each child. There is also a procedure that allows eggs to be fertilized in one partner and carried to term by the non-genetic partner, allowing both women to be involved in the process by carrying the same child. 

As children’s rights defenders, we know that the “right” to have children should never involve intentionally denying children their natural right to their mothers and fathers and their right to not be commodified. As much as those striving for parenthood deny that genetics don’t matter when it comes to building a family, the efforts for biological connection that are undertaken when creating children in laboratories through donated gametes and surrogacy illustrate precisely the opposite. This begs the question, do genetics matter or do they not? Adults brazenly admit that genetic connection matters when it satisfies their wants, so why wouldn’t genetic connection also matter to children? As is evidenced by our story bank, genetic connection does matter to children, as much as adults try to deny it.

It’s Not Therapeutic, it’s Eugenic

Can we really say that Mitochondrial Replacement Therapy is a restorative, therapeutic process that is nothing more than a simple “cure” for a genetic affliction? Considering the destruction of human embryonic life, reversion risk,  selective reduction, sex-selection, health risks, permanent heritable alterations, and the risk of the child’s identity crises, MRT is not therapy. MRT is trial-and-error experimentation in an attempt to perfect a risky, eugenic procedure with real human lives as the materials.

Only a handful of babies have been born using MRT, but this is the first time intentional genetic modifications have been allowed, and these modifications will open the door to further modifications fraught with unforeseeable consequences. Treating children as commodifiable objects will also allow for continued condoning of practices such as cloning, artificial wombs, the faster and cheaper discarding of embryonic persons who don’t “make the grade,” artificial embryos, and creating sperm and eggs from skin cells. We must stop treating children as artifacts brought into existence “in accordance with humanly-established parameters in order to satisfy a certain standard.”