Why the US Should Follow Britain’s Historic Decision to Approve Mitochondrial Transfer, i.e., “Three-Parent Babies”

three-parent baby

Part 1 of a 3-Part Series on 3-Parent Babies:

In the summer of 2011 I took Professor June Carbone’s International Bioethics and Assisted Reproduction class where I first learned about an innovative in-vitro fertilization (IVF) technique known as mitochondrial transfer, or what is colloquially referred to as “three-parent babies” – much to the chagrin of many scientists. Since then, I have continued to study and remain up-to-date on the topic, which is why I was excited to read about Britain passing an amendment this month permitting IVF techniques targeting inherited mitochondrial diseases, making Britain the first country in the world to officially allow mitochondrial transfer. Once the Human Fertilisation and Embryology Authority (HFEA) approves the science, the procedure will assist thousands of women in the UK to safely reproduce without the fear of passing on certain devastating, and sometimes even deadly, mitochondrial genetic disorders.

The Treatment

For years now, it has been possible to diagnose mitochondrial diseases and debilitating conditions such as muscular dystrophy, leigh syndrome, diabetes mellitus and deafness, and various problems affecting a child’s heart, liver, and other vital organs… but then what? Parents and children are given very few treatment options and there is no cure for these horrible afflictions. According to recent estimates from the New England Journal of Medicine, nearly 2,500 women of childbearing age in the UK, and more than 12,400 in the United States, are at risk of transmitting mitochondrial diseases to their children. In Britain at least, these women will finally have the safe option to utilize mitochondrial transfer.

DNA, Scientist in Lab

Every human cell is comprised of two main parts: (1) the nucleus, which contains our DNA, the genetic code that helps shape our inherited traits such as your eye color, hair color, your dimpled chin, etc. – essentially the stuff many people think of as making you “you”; and (2) the cytoplasm containing the mitochondria, which are sometimes called the “battery” or “powerhouse of the cell” – the mitochondria are tiny organlike units within the cytoplasm whose job is to provide biochemical energy to every living cell. The mitochondria contain tiny amounts of their own DNA, which are maternally inherited. Even though there is only a trace amount of DNA in the mitochondria, when the DNA are defective and malfunction, it can be devastating.

IVF, Public Domain Photo

In normal IVF treatments, a woman’s eggs are harvested, combined with the collected sperm of a man, and then placed in a petri-dish for fertilization, creating a tiny embryo that can later be implanted into a woman’s womb. Building on this treatment, mitochondrial transfer is essentially the placement of the nucleus from the intended mother’s egg into the healthy mitochondria of a donor’s egg, i.e., the “third parent.” The fertilized egg is then implanted in the intended mother’s womb.

Unnatural Responses

The media’s sensationalized description of this treatment as “three-parent babies” has been unhelpful throughout the discussion and debate of this topic, intended only to illicit fear and concern of something unknown or unnatural – as if the child were a Frankenstein-like monster, born from a hodgepodge mix of three random people. However, the reality is far less dramatic because the words “three-parent baby” do not reflect the science.


Each mitochondrion contains a mere 37 genes; in comparison the nucleus contains 20,000-25,000 genes. Hence, over 99.9% of a child’s genetic makeup comes from the intended mother and father. Granted, an important characteristic of the child’s health will be derived from the donor (otherwise there would be no need for the treatment), but the socially and ethically important characteristics of the child, including personality, talent, and physical attributes, all derive from the nucleus and sperm of the child’s true biological parents.

Beyond this though, most parents will tell you that parenting is so much more than the mere transfer of chromosomes. We have already seen that the family dynamic can include three- and sometimes four-parent families: gay couples with children via sperm or egg donation, step-parents, adoptive families, etc. Ultimately, the science behind this treatment does not equate to parenting; being a parent is a role each individual must choose on their own. Unfortunately though, deep-rooted ideas about “naturalness” have framed much of the discussion about mitochondrial transfer.

Addressing Concerns

While mitochondrial transfer allows a safe alternate reproductive method for the women who are carriers of severe mitochondrial defects, there are still those who voice concerns about the treatment. However, most of the concerns expressed amount to nothing more than pandering to uninformed constituents who have an ill-conceived notion that this treatment is genome modification within an egg’s nucleus leading to sensationalized “designer babies.” The reality is that this treatment is the transfer of an egg’s nucleus from a potentially lethal environment of defective mitochondria, into the safer, healthy donor’s mitochondria.

Arguments that doctors performing this treatment are “playing God” seems rather odd considering that doctors – in the sense of interfering with the natural course of events in order to increase the length and improve the quality of human lives – are required to “play God” every day. We, as a society, have asked doctors to address the predicaments of women, men, and families, and to assist whenever possible. Doctors have accepted this responsibility and now consider it their duty. Thus, whether performing a transplant to replace a naturally faulty heart, or delivering a baby by cesarean section because natural birth was dangerous or simply not possible, doctors are righting the wrongs of nature, which is the essence of medicine.

Some have argued that this is a slippery slope, but this argument has been raised whenever there is an advance in medicine, technology, or any field really. Moreover, the rigorous debate of both the science and public opinion that occurred before passing approval for this treatment serves as a perfect model of what will happen in the future. Thus, there is no “slope” because any ethically challenging future advance will require significant scientific research and vigorous public debate before moving forward. That is how progress is made.

There are some concerns that, although possibly valid, can all be addressed and ultimately do not warrant keeping the technology illegal. According to some experts, there are “unknown risks” associated with this treatment, but this is true of any new medical advancement. (It should also be noted that similar arguments were made when IVF was first introduced). Other experts have argued that the children will require lifetime monitoring, along with the children’s children, in order to identify any unknown risks to the child and future generations, such as faulty mitochondrial DNA transferring during the procedure and the possibility that some mitochondrial diseases are actually caused by something other than defective mitochondria, possibly genetic faults in the nucleus.

First, basic check-ups are necessary for anyone, and this would certainly be necessary for any children born to a mother with a mitochondrial disease without the treatment. Second, this is an argument regarding the technology’s effectiveness and the long-term impact it will have on the child, not against the technology in principal. Third, all of these concerns seem like a small price to pay in order to live a life free of the debilitating mitochondrial conditions. Finally, and most importantly, though possibly valid, all these concerns are ethically acceptable when informed consent of the parents is required, allowing the parents to decide whether or not the risks are worth proceeding with the treatment.

In the end, most of the opponents against mitochondrial transfer have tried to describe this debate as one between amoral scientists hell-bent on progress at any cost, and those who are supposedly seeking to advance science within a moral framework. But how is it morally correct to prevent medical advancement and treatment that would alleviate unnecessary suffering and misery for both parents and children? …It isn’t; rather it is only morally correct to inform and reform reproductive practice by introducing this life-saving treatment under appropriate regulation as soon as possible to give hope to thousands of families. Britain understood this when they made the ethical decision to embrace the future. I hope the US will do the same.

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