Defining The Spectrum of “Normal”: What is a Disease?

Bioethics-in-the-News-logoThis post is a part of our Bioethics in the News series

By Jennifer Carter-Johnson, JD, PhD

The world of Gattaca once seemed a faraway place where some babies had genetic defects corrected before birth resulting in two classes within society. However, a recent report that a Swedish scientist, Fredrik Lanner, has begun to edit the genome of healthy embryos has made the movie seem ever more probable. This report follows on the heels of reports from China that two teams have edited non-viable embryos to correct for a blood disease and to make the embryos more resistant to HIV infection. Embryo gene editing experiments have also been approved in the UK, and while the U.S. National Institutes of Health refuse to fund such experiments, some state funding agencies are beginning to consider it. The eventual goal of these experiments is to correct genetic diseases at conception, saving people from living lives with Huntington’s disease or with genetic predispositions for heart disease or breast cancer.

Part of the DNA sequences from the human genome
Image description: a page of a book displays part of the DNA sequences from the human genome. Image source: Flickr Creative Commons.

There are a myriad of concerns connected with the editing of human embryos as discussed in the reports mentioned above. Usage of embryos for any research is controversial since some believe that embryos should have rights equal to a born person. Beyond the basic question surrounding all embryonic research, scientists have questioned whether we should be creating designer babies, citing concerns that the use of embryo editing might inadvertently create new diseases. Additionally, access to the technology might be limited due to the high cost, giving rise to a situation where those who can afford to edit their child’s genome will have the advantages of selecting for children who are highly intelligent, highly athletic and low health risks. In a society where class inequalities are becoming ever more pronounced, use of embryo editing could exacerbate the problem by unevenly allocating not only resources but also abilities to those with money.

Perhaps one of the most difficult questions to be answered relates to which genes should be modified. As an abstract concept, using embryonic gene editing to cure a disease is more palatable to many than choosing eye color and height, but identifying a “disease” may be more complicated than it looks. As researchers identify the genetic basis for conditions that impact a person’s health, it forces us to ask if those conditions are diseases or merely a variation on the normal of human existence.

Some mutations that increase susceptibility to disease are actually beneficial mutations in the response to other diseases. The mutation that leads to sickle cell anemia protects against malaria in people who only have one copy of the mutation. Mutations in the T cell receptor CCR5 make a person more susceptible to psoriasis and infection by West Nile Virus but protect against HIV and smallpox infections. Obviously, we don’t know all the mutations that are beneficial against diseases, merely that some people get more or less sick when confronted with certain pathogens. It is possible that super-healthy, specifically-designed children would be ill-equipped to defend against an emerging disease where some members of a genetically diverse population would have protection.

Image description: a bright blue frame surrounds an artist’s embroidered rendering of the human chromosome map. Image source: Flickr Creative Commons.

Other disease-causing genetic mutations may also shape traits that society views as a positive. For instance, some research links the genetic predisposition for bipolar disorder with high IQ and enhanced creativity. Would the individual or society benefit from ameliorating the former at the cost of decreasing intelligence and creativity? Conversely, if the intelligence and/or creativity are genetically linked to bipolar disorder, well-meaning parents, seeking to increase the potential of their child, may exacerbate a genetically related mental illness.

Finally, one person’s disease is another person’s normal, community and heritage. Deaf parents often resist cochlear implants in their deaf children. These parents don’t view deafness as a disability but rather a community with its own language and customs. This view stands in contrast to the views of many in the hearing community who view deafness as a defect to be cured. Indeed, most deaf people function well in both deaf and hearing areas of society. If embryonic gene editing became a norm, deafness might be “fixed” – a process that some in the deaf community would liken to genocide. Similarly, many in the autistic community refuse to define themselves as having a disease. Not too long ago, homosexuals were considered mentally ill, a view that has become anathema as research into and acceptance of alternate views of sexuality have grown. Understanding the genetic underpinnings of autism and homosexuality would open them to a similar debate about embryo editing.

Some variations from normal are not diseases, they are merely differences. Some diseases or predispositions to diseases mask a greater benefit to the person or to society as a whole under certain conditions. Still others are life threatening diseases that carry little to no benefit as compared to the harm. We don’t always recognize these alterations for what they are, which makes determining which genes to modify a very difficult task as embryo editing becomes more feasible.


Jennifer Carter-Johnson, JD, PhD, is an Associate Professor of Law in the College of Law at Michigan State University. Dr. Carter-Johnson is a member of the Michigan State Bar and the Washington State Bar. She is registered to practice before the U.S. Patent and Trademark Office.

Join the discussion! Your comments and responses to this commentary are welcomed. The author will respond to all comments made by Thursday, November 3, 2016. With your participation, we hope to create discussions rich with insights from diverse perspectives.

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  1. Gattaca, Sony Pictures Entertainment (1997).
  2. Rob Stein, Breaking Taboo, Swedish Scientist Seeks To Edit DNA Of Healthy Human Embryos, NPR, last accessed at
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  6. Charles Piller, California considers funding controversial research: editing genes in human embryos, STAT, last accessed at
  7. Pittman KJ, Glover LC, Wang L, Ko DC (2016) The Legacy of Past Pandemics: Common Human Mutations That Protect against Infectious Disease, PLoS Pathog, last accessed at
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  9. Allegra Ringo, Understanding Deafness: Not Everyone Wants to Be ‘Fixed’, The Atlantic, last accessed at

24 thoughts on “Defining The Spectrum of “Normal”: What is a Disease?

  1. Thank you for the insightful article, Dr. Carter-Johnson. I appreciated the cautionary statement about the editing of the genome possibly furthering the unequal distribution of medical resources and inherent abilities to those with the most financial support. On the one hand, it is exciting to see the progress being made in disease treatment and prevention. To me, experimenting with the genome is not inherently harmful if it promotes the treatment of deadly diseases. On the other hand, it would be potentially disastrous to see further separation between those who can afford genetic modification and those who cannot. This is particularly true given the relationship between money, gender, race, and class. Cultural separation between the privileged and underprivileged could become even more tense.

    It was interesting to see that embryo gene editing had been federally funded abroad. It made me wonder why the U.S would choose not to fund such things, either from a cultural, moral, or financial perspective.

    1. Generally, the U.S. only allows limited funding for research involving embryos and cells derived from them. The Dickey-Wicker Amendment specifically prohibits federal funds from being used for research that creates an embryo for research purposes or that destroys an existing embryo. Embryo editing, of course, falls under the latter. You can see a statement from the NIH Director about NIH funding here: .

  2. You raise some interesting questions, Dr. Carter-Johnson. I can appreciate your concern regarding genome editing and its potential to deepen already widening divides in society. I can also see some potential ethical problems, where it would be all too easy to go to far and create “designer babies”, a concept which I find morally questionable. I’m sure most would agree that the best use of genome editing would be to “cure” deadly diseases pre-birth. However, we know that as with everything, a good thing can be used to both good and bad ends. It will be interesting to see what the U.S. decides to do in the future regarding this research and intervention.

    As to your point that “some variations from normal are not diseases, they are merely differences”, I am not so sure. I can appreciate the point you are making and the thought you are provoking. However, I believe in objective truth, and as such I think that there is an objective standard of health. When a person is deaf, it is because there is a mis-functioning part of their body, not merely a part that functions differently (but effectively) compared to others. A deaf person’s perception of this is their own choice, and I applaud those who have chosen to live positively and adapt to their circumstance. But I don’t call it normal, because it is a lack of a function that most of society enjoys. I will also go so far as to say that I believe every person on earth suffers some “dysfunction”, whether it be physical, mental, spiritual, or otherwise. None of us here is perfect, but we are all aiming toward that higher standard of health, in whatever way we can. I am aware that what I am proposing creates a dangerous tendency to marginalize disabled populations, and I am in no way advocating that position. Each human is inherently valuable in equal measure. However, I never want to sacrifice what is true for the sake of trying to solve another existing problem. That being said, I respect your opinion, and I thank you for sharing it.

    1. I agree that there is an objective truth (someone has a particular mutation or not) but I i don’t know that I agree that it always translates to an objective standard of health (this variant of the gene is the “healthy” one) that applies in all situations – which is why this discussion as to which variations are differences rather than diseases is so interesting to me! Deafness is example is on the extreme end of the scale – absence of a sense that most of society has and would view as a disease but that the population who lives with it does not view as a disease. A more complex question are the T cell receptor CCR5 mutations which make one more susceptible to some diseases but protect against others. Which gene variant is the “healthy” one? Another more easily pictured example is eye color. Blue eyes are a genetic mutation where a lack of melanin results in increased susceptibility to glare and damage from UV rays (increasing risk of cataracts and some forms of cancer). Are blue eyes in the range or variation of normal or are they a defect that should be fixed if possible? How we view the mutations and resulting characteristics inform our debate on gene editing.

      Thank for you sharing your very interesting insights!

      1. I think I’m understanding a little more what you’re getting at here, and I would agree. There are some gene differences that cannot be so easily classified as a disease or disability, even though they may make an individual more susceptible to something undesirable. It is very interesting to think about. Thanks for the reply!

  3. Thank you Dr. Carter-Johnson for such an interesting blog topic. I can see both sides to this argument of ethics in embryo gene editing, and its complexity to each side. I do agree that if this was implemented in our health care system, unintended consequences could arise in the furthering of inequalities and disparities.

    As I was reading this, initially I did not have a push back against the embryo gene testing, seeing the benefits of it being a preventative procedure instead of a reactive one to diseases. But as I read on, I started to think about my brother, Steffan, who has autism. I thought, “what if my parents could have changed his genes so that he would not have autism?” (Assuming that it was possible), and I that is when I realized I am against genetic embryo editing. I believe that human beings should not have the right or power to change the fate of a child born into their intended genetic reality.

    Yes, people say things happen by chance, but my personal and spiritual beliefs tell me everyone is born into their environments with a purpose. That everyone on this earth has something to learn and something to teach in their life time. If that means that my brother’s purpose was to teach my parents and myself the gift of unconditional love and the power of advocacy through his autism, then I would never wish to change his diagnosis or disorder. My brother was placed into mine and my parent’s life for a reason, and I do not think that should be discounted by a scientific genetic reconstruction.

    My worries lie in the reality that there could become “designer babies” and that my brother, and anyone else living with a developmental disability’s lives will become discounted.

    1. I appreciate your comment and the love and value you place on your brother’s personhood in the face of his autism. If gene editing were to become the norm, we would certainly need to remember that those without “perfected” genes are as valuable to society and theirs families as everyone else.

  4. Dr. Carter-Johnson, thank you for this interesting article. I am intrigued with the idea you brought up in this article that “one person’s disease is another person’s normal”. While I don’t feel that individuals who are living a different “normal” should be discounted, I’m not sure I can get on board with the idea that finding a way to prevent people from having to live that different “normal” is a bad thing. I can understand that a process such as embryonic gene editing is something that one must be very careful with as the consequences are not fully understood. However, I can see benefits in “gene fixing”. One such benefit may be in the cost over time. Management of disease over time can be incredibly expensive. Also, when that different “normal” affects quality of life, such as an individual living with chronic pain, it’s hard to think that this different isn’t less desirable.

    The article also touched on the possibility that gene editing has the potential to give advantage to higher SES individuals and to increase the inequality between economic classes. I think that this is a valid point, however I don’t think that it would be a new thing. While SES may not make one individual more or less susceptible to disease (when filtering for environmental factors) than another, SES does currently play a role in an individuals ability to live with or through disease. SES may determine what treatments an individual has access to, thus altering disease outcomes.

    1. Your comment and Karah Ley’s demonstrate two different perspectives to the gene fixing dilemma that I think illustrate why we should be having these conversations now while the technology is advancing. Additionally, I see gene editing as possibly exacerbating an already existing divide between economic classes rather than creating a new one, so I completely agree with you there.

      Thanks for the interesting comments and perspective!

  5. Thank you for your thoughtful article. Philosophers (e.g. Boorse) have attempted to define value-less concepts of health and disease with mixed success. I would argue that health is in fact a value, and not a statistical measure, such that a person has the authority to determine if their condition is in harmony with their life goals.
    There will always be inequality in life. Some will have the means to provide their offspring with the very best opportunities for success, while others struggle merely to survive. There is a difference between being poor and being impoverished. Extrinsic definitions of health have the unfortunate consequence of making us feel health-impoverished, even when we are not health-poor.

    1. Thanks for the nod to philosophers of medicine. It would be interesting to think about how my ideas mesh with theirs.

  6. Thank you for this post, Dr. Carter-Johnson. It sounds like the possibility of embryo gene editing is closer than we imagined. I appreciate the differences you highlighted about the deaf and autistic community. Similarly, many people and their families who have experienced Huntington’s, heart disease, or other cancer as referenced in your post, often identify as being part of a community of caregivers or a cancer culture, and this also becomes a norm for them. I understand wanting to use modern medicine and science to preemptively “treat” a disease like heart disease or breast cancer before it even happens, as opposed to treating it later in life through chemotherapy. I wonder if parents who carry a genetic marker for these diseases, who have already been caregivers to a family member and identify this as being part of their family development, would choose embryonic editing for their unborn children; this isn’t just a health care choice for them but a choice to alter their family’s development. Also, genetic diseases might develop despite environment, but I also know that some diseases are more likely to develop based on the family’s nutrition, proximity to power plants, exposure to harmful chemicals in water, etc; and so at what point should we decide that this is a disease that would have happened anyway, or let the child grow to see if they will develop normally, or decide to treat a disease that is only happening due to human fault due to chemicals and harmful environmental factors? Speaking as a social worker and knowing what terrible living conditions some people in the world are exposed to, I would think that unborn children who are more likely to develop diseases because of their exposure to environmental causes, or something that is the fault of humans in general, should be the first to be considered for this embryonic treatment, to prevent these genetic mutations from being passed on and save their families from yet another generation of poverty and stress of caring for a sick child. This, of course, brings us back to the debate of who pays for health care and why, and how would this be determined, and of course your original question of how the genome interacts to provide protection from some diseases due to the genetic markers for others.

    I think we can all learn through this post that this is not a question that can be answered in just one comment. While some governments and funding bodies have already approved this, the religious, moral, and personal choices of people all over the world will continue to impact the development of embryo gene editing.

    1. Yes, genetics alone do not always cause the disease. Understanding the interrelationship between genetics and the potential environment of the child will be imperative in making decisions about which genes to edit. That undertaking is huge!

  7. Hello Dr. Carter-Johnson,
    I think this article posts some very interesting ideas and concepts. I recently learned of a PBS series called The Nine Months That Made You, and it discusses different birth defects around the world and how they are viewed, for example there is an island in the Caribbean with the entire population being colorblind. This might seem like a negative thing because they have trouble seeing in bright daylight, however, they see better at night and are able to fish at night which is beneficial to them. Or another community who views extra fingers as being special in the community. I believe that some people view their disabilities in different ways and it may not be negatively.
    I think that gene mutation and modification is a great thing to study and that the US should be working on it here as well. But I think that it is difficult if people do not have a right to self determination, which is hard if the editing is done at the embryo stage. I think that the eradication of certain diseases is very important. But I think that there needs to be caution when you consider mental or learning disorders. For example, I am friends with a couple who has a child with Down syndrome and they would never change that if they were given a choice. However, a lot of new parents might not make that choice.
    But in all honesty, who has the right to make these decisions and determine what classifies as the right or wrong gene to edit? I think that as with other controversial topics there is no specific right or wrong answer it is more of a case by case basis with the right to self determination. I think that it is great to keep differences in the population, but it is also beneficial to eradicate certain harmful diseases. And as in all situations there will be people who abuse the power and take it too far such as changing eye colors or making “designer babies”.

    Thank you for this interesting topic!

    1. Yes, this is not an easy question! Few would change the basic nature of their child once they know them, but might view crafting a potential child differently. That perspective difference is also fascinating.

  8. Dr. Carter-Johnson, thank you so much for writing an insightful piece!
    I think that this topic can be incredibly hard subject to understand, to think about, and to create a concrete answer on. Your mention of the unknown, and how if we modify certain genes it could create other disorders that we as a society may have not encountered yet was through provoking to me. I am not a scientist, nor am I a health professional but I do think that there is certain things in life that have yet to be discovered especially disease wise. Genetic modification is a rather recent phenomenon in human’s health. It can create answers to such diseases, help us understand the many mysteries of the human body but ultimately we still do not know everything. And perhaps these mysteries make us unique from each other. For example, defining health is all in the eye of the beholder. Each body is different, and health is a relative term in my opinion that can change from person to person. My health standard may be different from yours, and that is completely normal and to be expected. Our unique qualities are to be valued, not be diminished our shut down by societal standards of health, worth or the ideal life. I appreciate that this topic is under such scrutiny and debate in our country and is being thought out very thoroughly. Questions of quality of life, how do we value life, and what make us human are valuable questions to think of as a society.

    1. Thanks for your kind words. This is such a difficult topic that will be facing not only scientists and medical professionals but also potential parents of all backgrounds such that the conversation will become important for us all.

  9. This blog post really is fascinating. On one hand the idea of being able to prevent and ultimately end some disabilities and diseases is amazing and could really change a lot of peoples lives. On the other hand though this work really is trying to play God. Where would the line be drawn of what changes are acceptable and what ones are not. I personally would be afraid that this would be a slippery slope. That it would start as getting rid of disabilities and disease but could really evolve to a world of designer babies.
    I really liked that you pointed out that disabilities are defined differently by each person. There are a lot of families who have children who have “disabilities” by a textbook definition but their parents feel that those traits just make them who they are.
    Overall, I think there are a lot of really interesting points made and I am really curious to see what happens in this field in the next 30 years.

    1. It is all about balancing the good and the bad in the technology. The future is exciting – and a bit scary!

  10. Hello Dr. Carter-Johnson!
    Thank you for talking about this hot topic the medical community. I remember watching Gattaca in my high school biology class and, at the time, thought that the idea of being able to design your own baby sounded so cool and futuristic, but now that we are beginning to have the technology to actually design babies this idea is actually terrifying for me, for many of the reasons that you have stated, such as increasing a gap between the rich and the poor as well as eliminating something that some people take pride in (being deaf/ the deaf community).
    Another issue that concerns me with designing babies is taking out all possible mutations–not only does this take away “negative” mutations, but also prevents any possible positive mutations from occurring, thus stopping the evolution of humans as a species. By taking out mutations of all kinds we are stopping the progress of our species and possibly preventing discovery of more effective treatments for diseases (however you define them) such as a specific gene that is immune to HIV.
    Thank you for taking the time to read my thoughts on your article,
    Chelsea H.

    1. I love the idea that we would also be impacting the evolution of our species! Mutations play a huge role not just in disease but also in adaptation. Unfortunately, we don’t know which mutations will become valuable until they do.

  11. Hi Dr. Carter-Johnson, Thank you for you insight on this topic. I am not a huge fan of the idea of “designer babies”. When I have heard about gene editing in the past it was determining the eye color of the baby, possibly the height, so I did not see the point in gene editing. You brought up great points though that I never thought about. This article made me think, am I really against gene editing if it could potentially have beneficial effects on the baby? You made some good points though when you said that these “positive” changes might have negative effects in the long run, if they are more at risk for other diseases. I like the fact that you brought up the fact about some people in the deaf community being against cochlear implants. I think we, in the hearing community, do not realize how some people in deaf, feel in their own skin. We assume that they want to hear because we do, but they are fine living their lives without being able to hear and they do not feel the need to change.
    You mention the risk of creating new diseases with gene editing. Do you think these diseases could potentially be worse than Huntington’s disease or genetic predispositions for heart disease or breast cancer? Also, I would like to see what is happening with the gene editing being done in China and the UK. Are the gene editing successful? I know that gene editing could make its way to the US, I’m still apprehensive about it.
    Thanks again for you insight,

  12. I don’t know how bad the diseases created by gene editing could be. Worse than Huntington’s? – unlikely. Worse than a 20% increased risk of Heart disease that could be mediated with diet and exercise? Maybe. The risk must be balanced against the potential for and severity of the disease at issue. I do not believe there is one “right” answer for all cases.

    The success rates seem low thus far for the studies I have seen. But the Chinese studies used non-viable embyros and that may have impacted success rate. In any case, we are at very early stages of the technology.

  13. Dr. Carter-Johnson, thank you for taking the time to read my thoughts first off. I found your blog to be very interesting and honestly did not know embryo editing was as prevalent within medical research currently. In my opinion, this procedure/experiments seem to be very risky and it does not seem that “the benefits” would outweigh the risks. I understand the potential for embryo editing and how it supposed to “correct genetic diseases at conception” as you mentioned. This made me think of when I worked at a Psychiatric Hospital and worked with an older man in his 40’s; he coped with major depression from the development of Huntington’s disease in his 20’s. This man was unfortunately very suicidal and did not see a reason for living due to his disease that was literally taking over his entire body. Just like any major disease or any illness and disease for that matter, it can be very difficult not only physically but mentally, emotionally, financially, socially and etc. This can be difficult for anyone to go through and for any family member, significant other, caregiver and etc. to see their loved ones endure such pain and trauma.

    Though there are very many situations like this that families unfortunately end up in, in my opinion I really don’t think embryo editing is worth it. Even with the possible development of further research where research scientists become more “accurate” with selecting and changing what genes carry what, I feel that no matter how much research we do we will never completely understand the make-up and continuous development of the human body and genetics; I don’t think it’s meant that we are supposed to. The human body is very interesting and every human being is quite unique; the fact that there are some genetic mutations that decrease the mutation of other possible diseases is amazing and something medicine probably can’t even cure, let alone embryo editing (though this is certainly a case by case basis, especially with some of the examples you mentioned. To think of the positive outcomes to some genetic diseases like bipolar disorder, as you mentioned, is interesting as well.

    My point though, is there is so much we don’t know that could effect in a positive and also in a negative way what we do know that it’s just not worth it to even experiment with. I feel the human body will take care of itself in the way it’s meant to do so, this may not always mean a positive outcome; though, I do think that if this research was more accurate and proven to be safe, we could certainly save a lot of lives from unwanted genetic diseases. But then this opens this door to other issues in the equality of the poor and the rich and who can afford these experimental operations. So if we can make this embryo editing equally and fairly affordable, available, accurate and safe for all people, then this could possibly be an option (but that would mean we live in a perfect world). Thank you for the very interesting blog again Dr. Carter Johnson!

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