Human Genome Editing for Cognitive Ability

Human Genome Editing for Cognitive Ability
March 22, 2023 No Comments Genetically Modified Life Ariel Sykes

The Eugenics of Intelligence: The Promise and Perils of Human Genome Editing for Cognitive Ability

By Isabella Racioppi

The advancement of technology in the field of genetic engineering may soon make it possible to alter DNA so precisely that human traits may be edited with a few simple alterations to the human genome. One aspect of redesigning the human race is the idea of designing babies to be more intelligent. Proponents argue that society would benefit greatly from a more intelligent human race. Critics contend that human genome editing for purposes of enhancement, rather than for curing and preventing disease, would cross a line of no return thus bringing the world dangerously close to a debate regarding the ethicality of modifying genetic imperfections. This paper will explore the concept of intelligence and its genetic basis. It will then provide a brief summary of historical aspects of enhancing intelligence, followed by an overview of current genetic technology and an analysis of the issues posed by enhancing intelligence using such technology. This paper will then provide an overview of how future technological advancements will affect the eugenics of intelligence and will end by considering several ethical implications of genetic enhancement for intelligence.

Table of Contents


The advancement of technology in the field of genetic engineering may soon make it possible to alter DNA so precisely that human traits may be edited with a few simple tweaks to the human genome. One example of this genetic engineering is improving human intelligence. Proponents argue that society would benefit greatly from a more intelligent human race. Critics contend that human genome editing for purposes of enhancement, rather than for curing and preventing disease, would bring the world dangerously close to crossing a line of no return, thus sparking a debate about the ethicality of modifying genetic imperfections. This paper will explore that ethical debate beginning with a discussion of intelligence and its genetic basis. It will then explore a history of earlier attempts to enhance intelligence, followed by an overview of current genetic technology and an analysis of the issues posed by enhancing intelligence using such technology. This paper will then provide an overview of how future technological advancements will affect the eugenics of intelligence and will end with a discussion about the individual and societal implications of the genetic modification of intelligence. It should be noted, however, that the ethical discussions presented in this paper are based on the assumption that human intelligence can be manipulated genetically, and as we will see, this is far from the case at this time.


Each spring, college applicants anxiously await the results of years of study culminating in a decision that will influence the balance of their lives. Throughout their high school careers, students diligently maintain their grade point averages while spending a multitude of hours preparing for Scholastic Aptitude Tests, better known as SATs – all in the hope of being accepted at the best possible college or university. Intellectualism is so valued in our society that a multi-dimensional industry is devoted to college placement.  Having intelligence is, after all, considered one of the most admirable and valued characteristics in people. What makes intelligence so monumentally important in our society?   Better yet, what exactly is intelligence? There exists a myriad of definitions attempting to denote and capture the essence of intelligence. On the one hand, Socrates, one of the greatest thinkers and philosophers of all time considered himself to be wise, simply because he knew that he knew nothing. (“Socrates Quotes”). On the other end of the spectrum is the perception held by world-renowned physicist Stephen Hawking who is known to equate intelligence with the ability to adapt to change. (Hawking).  A more fascinating interpretation of the essence of intelligence is that of Albert Einstein who once said that the true sign of intelligence is not knowledge but imagination. (“Quotes”).

A more conventional definition is provided by Merriam-Webster where intelligence is defined as “the ability to learn or understand or to deal with new or trying situations: the ability to apply knowledge to manipulate one’s environment or to think abstractly as measured by objective criteria (as tests).” (“Intelligence”). In reviewing a compendium of definitions, only one thing is certain and that is that there is no one standard definition of intelligence. However, it is abundantly clear that most definitions correlate the meaning of intelligence with some sort of interaction with the environment. Intelligence, then, is the ability to learn from experience and to adapt to changing environments, the attributes of which include having the ability to reason, to think abstractly, to plan, to understand complex ideas and to solve problems.

Measurement of Intelligence

Intelligence is not a single discernable characteristic, but rather a multitude of abilities related to one another. The task of measuring the construct of intelligence is hardly a straightforward process. Practitioners in the field of psychology have long examined how best to capture the essence of human intelligence and cognitive ability in order to establish a quantifiable measurement. In 1904, psychologist Charles Spearman posited that a general factor of intelligence, which he referred to as g, represents the underlying mental capacity that impacts performance of cognitive abilities and tasks. Spearman’s g factor interpretation remains the dominant basis upon which attempts to measure intelligence are made.  It is well accepted today that an underlying mental ability influences performance on human cognitive activities.

There are many other influences on cognitive ability. Human traits have a significant bearing on how the g factor influences the outcome of cognitive performance on tasks. These include biological traits, cognitive behaviors, and personal motivations.  Socioeconomic influences and human behaviors also play a critical role in determining outcome. The construct of a g factor advanced the possibility of conducting psychometric examinations of general cognitive ability and human intelligence. Valuation methods are based on the concept that intelligence and cognitive tests are influenced by the underlying g factor where there are observed relationships between the scores and other measurements of g. For instance, students who perform well on an Intelligence Quotient (IQ) test often also excel in other conventional measures of success, such as academic achievement and economic success. It is well accepted that a well formulated IQ test is a good estimation of g. Similarly, intelligence is measured by standardized tests such as the Scholastic Aptitude Test which measures college readiness. Such testing, however, fails to provide a pure measure of cognitive ability when external factors are considered such as test preparation, school curriculum, fatigue, mood, and motivation. Moreover, there is debate about whether IQ scores and SAT scores are actual indicators of general intelligence or whether they correspond to special skills related to test-taking.

The Correlation Between Intelligence and Genetics

The construct of g is, by its very nature, extremely complicated as evidenced by the preceding discussion. Initially, the studies about genetic influences on g were about the degree of heritability. It has been well documented that intelligence is strongly influenced by genes. With advances in molecular genetic methodology, the focus then shifted to the study of which genes are associated with differences in g

Before proceeding further, a brief primer on genetics is warranted. Human beings are organisms that are made up of millions of cells each having a nucleus which contains DNA (deoxyribonucleic acid). DNA is an organism’s genetic material which carries the organism’s instructions for building, maintaining and reproducing cells.  DNA contains information about the function and structure of the organism. Genes carry vital information for the transfer of heritable characteristics to offspring. Genes are DNA sequences which determine an organism’s growth, size and other traits by controlling how proteins are made. The proteins are responsible for controlling each cell’s chemical reactions which, in turn, direct the manner in which cells grow and develop. Genes are also responsible for diseases. 

Genetic engineering is the science of artificially manipulating and controlling the genetic makeup of living organisms. The role of genetic engineers is to manipulate the genetic makeup by removing and replacing genes or by altering genes. In this way, genetic engineers can cause new proteins to be made which results in the organism’s traits being altered. Medical research in genetic engineering provides hope that altering genetic makeup could cure certain genetic diseases, such as sickle-cell anemia or Huntington’s disease. However, genetic research becomes controversial when its goal is to improve people’s traits, by making them smarter, more athletic or better looking. The debate becomes even murkier when we consider the effects of making perfect babies and releasing them into the biosphere to reproduce which could result in a loss of control over future species of human beings. 

The Number of Genes that Influence Intelligence

Geneticists agree that many genes each have small effects on human intelligence. Studies have been conducted about genetic variations across entire genomes of many people, an approach referred to as genome-wide association studies (GWAS), in order to determine whether certain areas of the genome  are associated with higher levels of intelligence than other areas of the genome. No one genetic locus was found to be associated with differences in intelligence. Rather, there are estimated to be approximately 10,000 gene mutations that account for differences in cognitive ability among people, with each genetic variant having only a slight affect on IQ. It is further theorized that a single mutation (an alteration in the DNA sequence that makes up the gene) can affect IQ negatively by half a point.  These studies confirm that intelligence is highly heritable, but also that it is more likely that a very large amount of genes is associated with differences in intelligence rather than any one particular gene.

The Combined Influence of Genes and Environmental Factors on Intelligence

Intelligence is a very complex human trait that is shaped not only by genetic composition, but by a broad range of environmental factors. Genetic and environmental influences in g are not independent of each other. Cognitive ability is affected by environmental factors such as home environment, type of parenting received, culture, nutrition and diet, quality of education, availability of learning resources, and friendship interactions.  A person’s intelligence is derived from a particular combination of genes and environmental factors, meaning that it is not derived from certain genes and the right environment, but from the right combination of genes and environment. Research on heritability studies indicate that intelligence is a trait with an estimated heritability of approximately 50% – 80%, and the balance is influenced by non-genetic environmental factors.  Research studies on twins, siblings and adopted children have been conducted to compare similarities and differences in IQ among family members. The studies reveal that their genetic makeup is responsible for about 50% of the differences in IQ.

Difficulties in Studying and Researching the Genetics of Intelligence

Onderwijsgek at nl.wikipedia, CC BY-SA 3.0 NL, via Wikimedia Commons

Despite the recent innovations in gene editing, editing embryos for a trait such as intelligence is currently unlikely to succeed because human traits do not completely originate from genetics. In other words, genes do not strictly determine the human organism. In order to program cognitive ability into a human embryo with gene editing, the trait must be 100% heritable, and it is not. As previously noted, an individual’s environment and genetic makeup influence each other and it is not currently possible to distinguish with any degree of certainty the effects of the environment from the effects of genetic makeup, or the combined effect of each. Additionally, the genetic variants interact not only with each other and the environment, but also with cellular and bodily environments, indicating that the sum total of genetic variants will not be likely to act as a predictor of intelligence. Also, in order for the gene modification to be successful, the trait must be caused by a single mutation or by an interaction between only a few mutations. When hundreds of gene variants are involved, it becomes impossible to edit genes in order to program intelligence with any degree of certainty.  

Another potential complexity in studying the genetics of intelligence is the theory that IQ mutations are additive such that the more gene mutations there are the lower the IQ score will be. However, it would be an oversimplification to theorize that the number of gene mutations can be totaled up to predict intelligence. Moreover, it is theorized that predicting IQ from birth will be more difficult because the effect of some genes will rely on the absence or presence of other genes. Studies of twins, siblings and adopted siblings have shown that inherited differences provide an explanation as to why individuals raised in the same environment have differing “levels” of general cognitive ability. While such traditional studies allow researchers to observe genetic differences without having to employ genetic technology, complex (and as of yet unavailable) technologies are necessary to pinpoint which genes account for observed differences in cognitive ability and how such genetic differences account for the variations. Much more evolved molecular genetics and significantly larger sampling sizes will be necessary to explain observed differences successfully. To put the difficulty of researching genes associated with intelligence into perspective, in 2014, researchers in one of the largest genetic studies of cognitive ability conceded that it would take a sample size of at least one million human genomes to identify even a small association with intelligence.

The History of the Eugenics Movement

In the late 1800s, British scientist Francis Galton postulated that the fittest members of society should be encouraged to have more children in order to improve upon the human race.  He called this concept “eugenics” which means “well born”.  Galton’s theory was that the quality of humanity could be enhanced by selecting for desirable traits. Galton’s goal was based, in part, on his desire to encourage people with high intelligence to breed more. As his movement progressed, it embraced the notion that the unfit, like those with low intelligence, should be discouraged from breeding. Meanwhile, his contemporary, Gregor Mendel, was making strides in discovering inheritance patterns of certain traits in pea plants. Geneticists began to apply Mendelian principles of genetics to the inheritance of human traits with the goal of improving the quality of the human gene pool by selecting for desirable traits. 

By the early 1900s, the eugenics movement led to a policy that controlled human mating and was embraced by scientists, physicians and lawmakers as a public health concern. It was based on the premise that by studying the genetic patterns of inheritance, undesirable traits could be removed from the human gene pool. The traits that they desired to eliminate included mental retardation, psychiatric disorders and physical disabilities. Initially, the movement was intended to prevent reproduction by genetically “unfit” people. As a result, the reproduction by unfit individuals was severely controlled. Unfortunately, this misguided attempt to improve the human race resulted in a program to prevent unfit individuals who were considered inferior (such as mental patients, prisoners, and indigents) from bearing children by implementing programs of involuntary sterilization and institutionalization.  Even the judicial system weighed in when the U.S. Supreme Court upheld the constitutionality of sterilization laws in Buck v. Bell in 1927 (“Buck v. Bell”).

The eugenics movement also targeted traits that had some genetic basis, but that were also largely influenced by environmental factors. This included “feeblemindedness”, which was a term used to define a wide spectrum of mental retardation and learning disabilities. Environmental factors such as inadequate education, bleak housing and poor nutrition were ignored as possibly influencing these traits.  At the time, what was believed about heritability was that complex human traits were controlled by single genes and could be inherited in a pattern that could be predicted, much like the genetics of Mendel’s peas. Early geneticists failed to realize that most, if not all, of the traits they were trying to eliminate from the human gene pool resulted from interaction between both genetic and environmental factors. 

The most notorious eugenics movement occurred in Nazi Germany in 1933 when 400,000 Germans were sterilized against their will for having physical disabilities, mental illnesses or for being “feebleminded”. When Adolf Hitler first adopted eugenics thinking to his belief systems, American headlines praised his sterilization policies. As history unfolded, Hitler moved from sterilization to mass murder and genocide in order to carry out his eugenics movement. In the process, he escalated the program to one of racial and ethnic hygiene and euthanasia, resulting in the deaths of millions of Jews during the Holocaust. This caused the American eugenics movement to retreat and the word “eugenics” took on a negative meaning. Today, eugenic philosophies have resurfaced in the debates ranging from designer babies to embryo selection and gene editing for purposes of genetic enhancement, leading some to fear the return of state-run eugenics programs. Critics of engineering a child’s intelligence say it is reminiscent of the discredited eugenics movement in the United States which tried to improve the gene pool of the human race.

Genetic Enhancement of Intelligence in Today’s Landscape

The re-emergence of eugenic philosophies has raised new interest in genetically modifying intelligence. However, for a trait such as intelligence to be programmed with gene editing, it would need to be entirely determined by heritability and DNA. The fact that intelligence is partially influenced by non-genetic environmental factors makes it unlikely that it can ever be genetically programmed. Moreover, intelligence is caused by a combination of genes which account for the actual variation of cognitive ability in the human population, making it impossible to target the right gene variants (known as alleles) for accurate editing using today’s technology. Even with the application of the right technology, at the moment of gene editing the future environment of the embryo is unknown, making it impossible to know what the right combination of genes needs to be given the uncertainty of future environmental factors. Realistically, polygenic traits such as intelligence are too complex and not genetic enough and, therefore, the possibility of genetic enhancement is unlikely to come to fruition.

It is worthwhile noting that many scientific milestones in history were achieved in the face of extreme odds. While the limitations of today’s technology make it seem improbable that an embryo’s cognitive ability may be determined genetically, it is certainly not impossible for such an accomplishment to come to fruition in the future. Proponents of designer babies anticipate being able to one day choose among a wide range of traits. The phrase “designer baby” is used by the media to describe reproductive technologies which give parents control over what traits their offspring will have. The next section will survey known reproductive technologies that may someday, with further advancement, prove capable of attaining the lofty goal of intelligence enhancement in human embryos.

Advanced Reproductive Technologies

A form of advanced reproductive technology known as pre-implantation genetic diagnosis (PGD) was developed in the 1980s and 1990s and is the process by which genetic disorders are identified in an embryo using microscopic examination. Certain inheritable traits can be artificially manipulated with this treatment-based genetic technique. Single cells are removed from embryos using the same procedure as in vitro fertilization. Embryonic cells are then examined for identification of genetic disorders. The embryos with the genetic disorder are discarded and those that are free of the disorder are implanted into the woman’s uterus. Using this process, certain genetically-based diseases can be identified, such as Downs’ Syndrome and Sickle Cell Anemia, and prevented from being passed on to the infant. Another use for this technology is treatment-based genetic manipulation of gender-specific disorders and diseases where the embryo is tested to identify the gender and the embryo with the gender that is likely to carry the trait is discarded. This technology may be adaptable in the future for selecting embryos having embryonic cells with genes for above-average intelligence.

marius walter, CC BY-SA 4.0, via Wikimedia Commons

A newly developed technology known as CRISPR-Cas9 has allowed genetic engineering to enter a phase where embryonic DNA can be manipulated with ease and precision using a pair of tiny molecular scissors. This editing technique makes it possible for genetic engineers to insert, remove and correct DNA easily and efficiently by altering the nucleotides of a DNA sequence. CRISPR’s safety and accuracy is improving at a rapid pace and it is also inexpensive. The technique is used to study disease treatment and prevention, and may one day be capable of modifying and editing genes to enhance traits, such as intelligence.

Another process that may be used in disease elimination is germ line modification. Human germ line engineering is a process that eliminates a disease or disorder from all future generations, thereby rendering the disease or disorder no longer heritable. Unlike PGD, which is a form of genetic screening that affects only the immediate offspring, germ line engineering manipulates the genes that are carried by the egg and the sperm and in so doing, affects all succeeding generations. It is possible that germ line engineering can be used for purposes other than disease elimination, such as modifying traits like intelligence along generations and not just immediate offspring.  This application is much more consequential to the human race in that it may result in the alteration of the human species.

The Human Genome Project began in 1990 as a monumental undertaking to map the human genome (or the complete DNA sequence in a human being), and was successfully completed in 2003.  Originally, the number of genes in the human genome was estimated to be 100,000, but has since been lowered to a range between 20,000 and 24,000. The project advanced the study of how DNA affects human development. Future insights about the human genome raise the likelihood that prenatal screening will soon lead to identification of genetic mutations that are correlated with specific traits. Understanding the complex human genetic code increases the possibility that parents may one day be able to select an embryo with desirable genetic traits, such as intelligence.

While the prospect of genetically engineered super-intelligent human beings is only a distant possibility, significant progress in the immediate future may give way to the ability to accurately predict cognitive ability. Our unfolding understanding of the human genome combined with the use of statistical algorithms, decreasing costs of genotyping and rapidly evolving technology will give rise to genomic-based predictors of intelligence in the near future. The availability of such predictive models when applied to selection of the “best embryo” (using PGD techniques) and genetic editing (using CRISPR techniques) may one day lead to staggering results.

Safety Concerns of Genetic Engineering

Critics of embryo editing worry that there may be unforeseen and unintended consequences. A group of scientists in 2015 (the UNESCO International Bioethics Committee) called for a voluntary moratorium on genome editing of the human germ line for fear that hereditary modifications could be passed on to future generations.  The UNESCO scientists stated that germ line modification of the human genome would “jeopardize the inherent and therefore equal dignity of all human beings and renew eugenics.” (“UNESCO panel of experts call for ban on “editing” of human DNA to avoid unethical tampering with hereditary traits”).

In December of 2015, more than 150 scientists met for the International Summit on Human Gene Editing in Washington D.C. and called for a global ban on the practice of human genome editing, claiming it could “irrevocably alter the human species” and lead to a human existence where discrimination is “inscribed onto the human genome”. (Knapton, “Humans will be ‘irrevocably altered’ by genetic editing, warn scientists ahead of summit”). They called for rules that respect human dignity and human rights. The basis of their concerns is that alterations in a person’s genome changes their genetic composition and such changes could be passed on for generations through the germ line of sperm and eggs. Once that happens, the original genetic makeup is lost forever.  Also, mistakes made during those alterations may have irreversible consequences. Such an outcome was inadvertently demonstrated by Chinese researchers earlier that same year in their attempts to alter genes in human embryos. While seeking to modify DNA to target the gene responsible for a deadly blood disorder known as thalassaemia, they targeted the wrong places of the DNA in some embryos. This attempt involved editing a trait caused by a single gene variation, not an interaction among multiple genes, and yet the wrong area was targeted. This has raised substantial concern about the consequences of germ line editing. Yet another paramount concern is that altering genes that we pass on to our children will never be accomplished without substantial trial and error, which brings about the realization that if humans are to be genetically enhanced for intelligence or otherwise, society must learn to tolerate mistakes and the ensuing creation of severely defective human beings. Clearly, this is not an option. The process would have to be perfected before it can be used on human subjects. But is that even possible?

Legal Landscape for Genetic Engineering

A survey of international regulations reveals a wide variety of legal attitudes regarding genetic engineering on human embryos. Some nations ban such modifications through the application of criminal penalties, while others are more lenient. There are regulations that consist of legislative bans, guidelines for bans, restrictive laws and ambiguous laws. Some countries incorporate their regulations into laws, while other nations delegate the responsibility for case-by-case review to smaller professional agencies and groups outside of the government. Equally diverse are the mechanisms for regulation and enforcement of such laws. 

As recently as 2014, a survey of 39 countries conducted by a Japanese bioethicist revealed that 29 nations had laws that seemed to restrict clinical editing of the human genome; in some cases, however, they were merely guidelines and were not enforceable as in the case of Japan, India, Ireland and China. Nine other countries had ambiguous laws. 

Resulting from such an ill defined legal landscape, legislatures around the world are slowly awakening to the need to acknowledge the monumental strides made in this increasingly expanding field of science. The most recent technological advancement, CRISPR-Cas9 has caught legislators off guard as they begin to realize the unprecedented possibilities available to genetic engineers in the use of this powerful tool. The theoretical feasibility of manipulating the DNA of a human embryo to address heritable human diseases is overwhelming when one considers the application of this technology to the germ line. Inevitably, CRISPR will be used for non-medical purposes when one considers the blossoming interest in designing babies by introducing, enhancing or eliminating certain traits. Clearly, the international legal communities have not kept pace with the likelihood of unintended and unexpected consequences that this unchecked technology may have on future generations. 

Legislatures will need to take into consideration how scientific advancements that alter the human genome would benefit society. For example, the process of in vitro fertilization coupled with PGD has enabled many women to avoid giving birth to children with serious diseases. Gene therapy holds similar promise, as does embryonic stem cell research. Legislatures are likely to consider the counter arguments equally compelling.  Genetic engineering of human embryos enables the wealthy to select the genetic composition of their children leading to widespread concerns of classism. Also, germ line engineering may have vast unintended and unforeseen negative consequences such as mishaps causing mutations that could be passed on through the generations. 

In the face of such benefits and detriments, regulatory authorities have struggled with how best to enact legislation that would be broad enough to allow useful medical innovations to continue, yet contained enough to avoid the potential for alarming and ominous consequences. Moreover, the pace of technological innovations is so rapid that laws and regulations are quickly rendered moot as the standard of care changes. This quandary has resulted in vague and ambiguous legislation about what constitutes an appropriate standard of care. Inconsistent international regulation of genetic engineering may lead genetic engineers and scientists to cross borders into nations where research may lead to clinical trials. 

In February 2016, the United States Director of National Intelligence added gene editing to the list of threats posed by “weapons of mass destruction and proliferation” because of the fast pace of developing gene editing technologies, its broad distribution and relative low cost. The Director stated that there could be economic and national security implications due to the technology’s possible uses, which include deliberate and unintentional misuse, and which may result in the creation of potentially harmful biological agents and products such as pathogens. This sentiment is echoed by scientists and ethicists who fear that genetic engineering can and will be used for destructive purposes. The concern is deepened, however, by the realization that if the proliferation of weapons of mass destruction cannot be controlled through international consensus, how can military uses of biotechnology be regulated? 

Also in February of 2016, the United Kingdom Human Fertilization and Embryology Authority (HFEA) approved a study which will use CRISPR to alter viable human embryo genes with the goal of studying the genes that lead to miscarriages.  Their hope is that the research will lead to the discovery of improved fertility treatments. The study was approved in part, because it was set up so as to avoid germ line alterations by not transferring the embryo to a woman or disallowing the embryo to develop beyond a period of fourteen days. While certain safeguards were adequately addressed by the HFEA, not all gene-editing projects around the world are regulated for safety.

Most recently, in June 2016, a United States federal bio-safety and ethics panel approved the first study using CRISPR-Cas9 gene editing technology on cancer patients. [30]The technology will be employed to create genetically modified cells to attack the cancer cells. The study was pending review and approval by the Food and Drug Administration which manages experimental treatments on people. The approval of this trial marks the first example of federal approval for the use of CRISPR technology on humans in the United States. 

It is interesting to note that the Nuremberg Code, which is a body of ethical norms used by the Nuremberg Tribunal following World War II to judge the atrocities committed in death camps, is cited by opponents of the practice of harvesting and discarding embryos. The belief is that the ethical norms of the Nuremberg Code, which are universally accepted today, should be applicable to genetic research and testing because human embryos are human beings and that, therefore, discarding embryos destroys human life in violation of the Nuremberg Code. 

It is also worthwhile noting that the American Medical Association has a Code of Medical Ethics which opposes genetic enhancement. It states, “Because of the potential for abuse, genetic manipulation to affect non-disease traits may never be accepted and perhaps should never be pursued.” (American Medical Association, Opinion 2.11).

There is a concern and fear that international regulatory frameworks and world communities are only just beginning to understand the full implications of genetic engineering of humans and the immense challenges posed by these technologies.  Some ethicists and scholars fear that the race to develop a superior human being could become a competition between nations. Ideally, an agreed upon international policy for human genome editing would result in the best case scenario, but of course, enforcement of these policies may also pose difficulties.

Current Controversies Surrounding the Study and Research of the Genetics of Intelligence

Research about intelligence raises controversial ethical concerns because the interpretation and analysis of the data will inevitably be used to explain deviations and variations by grouping people with respect to their cognitive abilities. The belief that intelligence is inherited and that some groups possess more intelligence than other groups is divisive and is unlikely to be provable. More particularly, research on the genetics of intelligence will likely lead to comparison between genders, socioeconomic classes and racial groupings, perhaps giving way to racist and classist agendas. Clear and consistent standards for researching intelligence must be developed in order to formulate research that is neither biased nor discriminatory, if that is even possible. 

Another controversy surrounding the results of intelligence research is that studies may be based on the questionable assumption that certain groups are limited by their genetic makeup without regard to non-genetic variables, such as unequal access to education and limited availability of opportunities. Research about observable differences in the cognitive ability of different groups must take into account their social environments as well as genetic factors. Also, it is important that the research be neutral because there are implied and explicit biases in explaining observable differences in cognitive ability among groups. Many ethicists have called upon geneticists to impute trustworthiness into their research by minimizing the possibility that the results of the study can be misinterpreted by bias and devalued by classism and racism. However, this is a tall order when you consider that the studies tend to involve very large sample sizes which take into account genetic ancestry and which necessarily lead to implied bias about race, ethnicity, nationality, gender and social status. The importance of observing relevant environmental variables to explain the resulting variations cannot be overstated. Intelligence research becomes controversial when its heritability is compared between genders, socioeconomic classes and racial groupings. Studying intelligence became very unpopular after a book called The Bell Curve: Intelligence and Class Structure in American Life attempted to quantify and study intelligence and discussed the implications of racial differences in intelligence (Herrnstein and Murray).  Even IQ researchers are in disagreement as to whether IQ scores can be validly compared between groups of people because variations within groups are more widespread than between the groups themselves, making it harder to draw a conclusion about a particular person. In general, people become uncomfortable talking about IQ because it tends to conflict with the notion that they are responsible for their own accomplishments through hard work and because the idea that some people might be born likely to succeed through inherited intelligence is considered somewhat distasteful.

What do Future Technological Advances Hold for the Genetics of Intelligence

Without a doubt, the ability to predict cognitive potential would have enormously beneficial applications in identifying genetic disorders. Such cognitive challenges could be decreased or even eliminated with PGD. This reproductive technology is a not just a means to prevent diseases or disorders.  In the future, parents may be able to use this technology to choose their baby’s gender.  This is where the notion of creating a “perfect” or “better” baby may lead to the desire to screen embryos for genes affecting traits like athleticism, height, eye color, musical ability and even cognitive ability. If the ongoing study of the human genome eventually identifies the specific genes responsible for particular traits (assuming they are single-gene traits and completely determined by heredity and not environmental factors), then the selection of traits would become merely a matter of screening embryos. As we have seen, however, cognitive ability is a trait influenced by the interaction of many genes and is greatly affected by environmental and social factors. Nonetheless, great strides are being made by companies striving to study thousands of genomes in order to find the genetic basis for IQ with the goal of embryo screening for intelligence. The belief is that the greater the number of human genomes that are studied, the more likely it is that the genetic code for human intelligence will be identified and that genome sequencing will reveal which genes are associated with intelligence.

If the genetic code for intelligence is ever identified in the human genome, then it is likely that CRISPR’s gene editing techniques may have a future application in enhancing cognitive ability. At the moment, its accuracy in targeting the right sites is limited by the fact that every human genome is unique. Moreover, its current capability is to target genes for diseases or conditions that have a single gene abnormality. With future technological advancements, however, the possibilities extend beyond eliminating disease and treatment-based gene manipulation because theoretically, the human species can be altered by genetic enhancements using CRISPR, including cognitive ability. CRISPR technology brings about the possibility of germ line editing of intelligence traits that may have far reaching consequences, such as a re-emergence of eugenic goals.

An ongoing and interesting discussion concerns the possible application of the genetics of intelligence to optimizing learning experiences for students. Studying the genomes of children may aid in the development of educational interventions which are tailor made to their genetic makeup by addressing their particular learning styles. The concept of personalized education where genetic research identifies educational interventions that fit students’ particular learning styles has been criticized because it is impossible to predict educational progress purely on the basis of genetic makeup and because not all schools have the same resources available to them. Also, research about personalized education may end up reinforcing the problems that created the disadvantages in the first place.

Individual and Societal Implications of Intelligence-Based Genetic Engineering

The concept of intelligence-based genetic engineering leads to both individual and societal considerations, as there are many unanswered questions and unaddressed issues creating widespread concern among ethicists and scientists. A survey and discussion of some of the more prevalent implications are presented in this section. 

The Principle of Beneficence and its Effect on the Individual

In the field of medicine, doctors are guided by moral principles in deciding whether the benefit of a medical treatment outweighs the risk of harm to a patient. Beneficence is the obligation to place the patients’ best interest and well-being above all else in making medical decisions. This moral principle also guides practitioners in the field of bioethics.  However, the concept of beneficence is more encompassing in ethical theory – it refers to a moral obligation to act for the benefit of others in order to further their interests by removing or preventing possible harm. Unfortunately, there is no universally agreed upon method to prevent harm and facilitate well-being when faced with the moral quandary of how different people are impacted by the same set of circumstances, as is the case with electing to genetically enhance a trait, such as intelligence. 

Parents may perceive that there are benefits to their child having enhanced intelligence, but how far do the range of benefits actually extend for the child? Not having had the opportunity to have granted consent, will the child ultimately agree that the parents’ actions were beneficial to him or her? Proponents rely on the argument of beneficence to counter that parents have a moral obligation to select the embryo or enhance their child’s genes to provide them with the best chance at an optimal life. Whistle blowers, however, cite dark memories of the eugenics movement and fears of resurfacing discriminatory and racial practices. Opponents claim that new techniques of genetic manipulation that are used to enhance traits such as intelligence amount to  nothing more than embryo selection for the purpose of selecting more fit future children, which they contend was the very essence of the eugenics movement.

Designer Babies and Market-Based Concerns of the Individual

Are parents acting like consumers in editing embryonic genes or in choosing embryos and desiring only a few while discarding the rest? Genetic screening using amniocentesis has enabled parents to test their babies for genetic disorders and diseases. PGD has the potential to take this a step further by enabling parents not only to discard a specific embryo but to choose the embryo they want. In so doing, PGD may expand the process of in vitro fertilization from a fertility treatment to a consumer based process where parents can pick and choose embryos like consumer goods. CRISPR technology provides the ability to edit genes and perhaps even improve them. Opponents of genetic engineering contend that genetically selecting an enhanced trait, such as an above-average level of intelligence, objectifies children like manufactured products that can be purchased for a price.

As we have seen, there are many reasons for genetic enhancement by embryo selection or gene editing if the technologies evolve to that point. They include screening for high risk diseases, gender selection, choosing specific traits, and genetic manipulation for therapeutic purposes and cosmetic reasons. It is a worth-while exercise comparing and contrasting the arguments in favor of and against designer babies. At the current time, these techniques are not feasible, but scientific breakthroughs may soon make some or all of these technologies possible. 

 There are many arguments in favor of designer babies. Parents are burdened with enormous financial and emotional strain from the debilitating diseases and deformities with which their children may be born. As parents that want the best for their child, shouldn’t they be able to use available techniques to prevent genetic diseases and disorders? Well-intentioned parents provide food, training, exercise, and education for their children in order to make them smart and healthy. So why not use reproductive technology to provide the same enhancements?  Parents seek the help of fertility clinics where they invest tremendous time and money trying to conceive a child. Shouldn’t these efforts be accompanied by the ability to have a healthy baby? Nature regularly rejects from the womb naturally conceived embryos having defects. Why can’t parents do what nature is already doing? Organ transplantation is regularly done today, although it was once thought to be “unnatural”. How is the replacement of a defective gene in an embryo any less natural than the replacement of a defective organ?

There are many equally compelling arguments against designer babies. Correcting traits in embryos is a slippery slope which may lead to the elimination of embryos simply for the purpose of having undesirable traits (this technology is rejected on the same pro life basis as abortion). It would be unfair for the procedures to be available only to the wealthy. Breeding a race of super humans may result in classism and discrimination where those without genetic enhancements or with inherited diseases and disabilities will be considered inferior. Tweaking the human genome may result in unintended and unforeseen results that could have grave consequences for human kind. For example, some of the world’s greatest thinkers, musicians and artists have had mental illness such as depression that have caused them to suffer greatly in their lives, but which inspired them to create beautiful works of art, music and thought. There are moral and religious reasons (which are outside the scope of this paper) for objecting to terminating embryos which is a necessary part of the procedures. Finally, critics of such consumerism argue that parents already have significant control over their children’s characteristics through their selection of mates. Parents choose their child’s genes even when they choose their partner. As Harvard psychology professor Steven Pinker states, “Anyone who has been turned down for a date has been a victim of the human drive to exert control over half the genes of one’s future children” (Pinker, “The Designer Baby Myth”).

Individual Decisions and the Ethics of Giftedness

“To appreciate children as gifts is to accept them as they come, not as objects of our design, or products of our will, or instruments of our ambition.” (Sandel 45). Such is the basis of the ethics of giftedness as proclaimed by the author of an often cited book The Case Against Perfection. Michael J. Sandel argues that the drive to enhance human traits is objectionable because of values such as fairness and safety, but also because it fails to appreciate the gift of human life, which is to appreciate children for who they are, not as products of our design. Bioengineering our children to provide them a competitive edge, such as providing them with enhanced intelligence, is an attempt to change the nature of children to fit into the world instead of making the world a place where gifts and limitations of imperfect human beings are welcome. According to Sandel, the benefits of this way of thinking will never outweigh the costs. Opponents of practices like PGD argue that genetic screening encourages parents to view embryos as desirable or undesirable, as though children are manufactured objects rather than unique gifts.  Equally compelling is the counter-perspective shared by Australian ethicist Julian Savulescu in his article, “Breeding Perfect Babiesin which he presents his case for  genetic engineering and designer babies. He contends that screening for certain genetic diseases may be beneficial for a child, but there is nothing wrong with taking it a step further in giving our children the best possible genetic start in life by selecting non-disease traits for them, thereby giving them the “greatest range of gifts possible”. (Savulescu, “Breeding Perfect Babies”). According to Savulescu, parents have a moral obligation to give their children the best life possible by providing them with optimal talents, skills, mental abilities and physical features.

Fairness Within a Society Will Be Compromised

Much has been written about the lack of fairness that unequal access to genetic enhancement and gene editing technologies brings about and whether it will lead to classism in genetics. Wealthy parents will be able afford expensive technology enabling them to choose “better” embryos or edit the DNA of their embryos to make them smarter, stronger, and fitter. Only those that can afford the technology can procure the advantages for themselves and their children and descendants. In a society where only the affluent can provide high IQs to their children, social tensions are sure to follow.  

genetic engineering by Kamin Ginkaew from Noun Project

If such technologies are unaffordable for people with lower resources, it may lead to a lower class that is considerably genetically inferior to a super human race which in turn may look down on the lower class of humans without genetic enhancements. To counteract such discrimination, parents may choose to enhance their children by diverting limited resources from elsewhere. Proponents of genetically enhancing for intelligence contend that the role fairness plays is to level the playing field between those who have a higher capacity for intelligence and those who have a lower one. Theoretically, the stigma for having less than average intelligence would eventually disappear. Clearly, however, this theory is rendered moot when one considers that differences in intelligence are based on interactions among many genes and that environmental factors play a substantial role.

Societal Implications of Re-designing the Human Species

A newly emerging socio-political ideology is called techno-eugenics. It consists of human genetic manipulation and selection that is technologically-enabled. Princeton University molecular biologist, Lee Silver, foresees a future in which “the health, appearance, cognitive ability, sensory capacity and the lifespan of our children all become artifacts of genetic manipulation” (Siedler et al. 36-37). He is keenly aware that the financial resources will limit the overall implementation of the technology, but predicts that, over time, society will consist of two tiers: the “GenRich” and the “Naturals”.  In his view of the future, the GenRich will account for 10% of the American population and will all carry synthetic genes. They will control the economy, the media and entertainment industry and the knowledge industry. The Naturals, on the other hand, will consist of low-paid laborers or service providers. Eventually, the two will become entirely different species and will lose the ability to cross-breed. 

In that scenario, it would not be hard to imagine what would happen if cognitive ability were engineered in embryos through the human germ line.  The two classes of humans could become two different subspecies of human beings – those that are engineered with intelligence enhancements and those with unaltered cognitive ability. Eugenic enhancement seeking to reproduce particular traits into the human gene-pool would actually limit its diversity thereby weakening future generations. Imposing man-made processes on the natural environment would introduce new combinations of genes into the human gene-pool and would decrease its diversity. For example, a new species of human being would be created that would be incapable of mating with unenhanced human beings. The biotechnology industry’s development and commercialization of human germ line engineering is progressing almost completely unregulated. For example, in 1999, Advanced Cell Technologies of Worchester, Massachusetts, created a human/bovine trans-species embryo by implanting the nucleus of a human egg into the egg of a cow. No laws were in place to have prevented an implantation of this egg in a woman’s uterus and yet a child born under these circumstances would have contained a small amount of cow genes. Organized opposition to techno-eugenics has been largely absent because people are not fully aware of its existence and there hasn’t been time for them to fully comprehend the implications of this technology, let alone to organize an appropriate response. Also, people respond to stories of re-designing the human species as mere hyperbole and science fiction, akin to Brave New World. Advocates of this daring new technology are rushing to create the first designer baby before the world catches on about what is actually at stake.

Dark Memories of the Eugenics Movement and Societal Implications of Liberal Eugenics

Critics of genetic engineering argue that “so called” enhancement is actually a return to eugenics of the discredited movement, but in a “privatized” or “free market” approach. Supporters contend that genetic engineering is not like eugenics because there is no coercion involved. The question becomes, is manipulating genetic structure in a non-coercive manner a bad thing?

An example of a “free market” eugenics policy took place as a state-sponsored policy in Singapore in the 1980s. The prime minister, Lee Kuan Yew, noted that fewer educated women were producing children and that less-educated women were producing more children.  He feared that the pool of educated and talented children would be depleted over the course of future generations so he instituted financial incentives for college graduates to marry and bear children. He also offered to pay $4000 down payments on low-cost housing for low-income women that lacked a high school education, provided they agreed to be sterilized. While this state-sponsored free-market approach did not force sterilization, critics asserted that offering a financial inducement is the same as coercion and that the act of genetically designing future generations of children is objectionable. Since no one is obligated to purchase or sell eggs, does it rise to the level of coercion? Is freedom of choice enough to put aside negative connotations of eugenics concerns? 

“Free market” eugenics policies have also been attempted in the American private sector. An American sperm bank opened in 1980 with the eugenic goal of improving the human intellect. The bank attempted to collect the sperm of Nobel Prize-winning scientists in order to create super-intelligent babies. As it turned out, Nobel Prize winners did not want to participate in such a scheme and the sperm bank failed. That sperm bank was criticized by another sperm bank in California for its eugenic goal, yet this business maintained offices near Harvard, MIT and Stanford in an effort to recruit intelligent donors and to market the prestigious pedigree of its sperm donors. Did these sperm banks have eugenics policies because they sought to deliberately design the intellectual abilities of children?

Circumstances such as these have led to a liberal interpretation of eugenics referred to as “liberal eugenics”, which means genetic enhancement without coercion and without state involvement. Liberal eugenics policies attempt to fairly allocate the burdens and benefits of genetic enhancement. This prevents placing the burden disproportionately on the weak and poor by segregating and sterilizing them. Rather than segregate and eliminate the unfit, the goal of liberal eugenics is to improve upon them by enhancing them to the highest genetic level possible. According to the principles of liberal eugenics, parents have a duty and moral obligation to improve on the human species by enhancing their child’s well being with the best possible genetic makeup. In doing so, the child will achieve their highest potential, thereby improving upon the human species. Proponents of liberal eugenics claim that the policy is about individual choice and not social reform. It is about a child’s autonomy and right to an open future, which is claimed to be ethically permissible as long as the child’s path is not directed toward a particular career or course in life.  In other words, a child that has been genetically enhanced for intelligence should be able to carry out any whatever plan of life they embark upon.  

Critics of liberal eugenics contend that such policies actually violate autonomy and equality. A child that has been genetically enhanced cannot state with certainty that they are the sole architect of their future. Moreover, equality is undermined because parents that genetically enhance their children undertake a responsibility that can never be reciprocated. To this critique, defenders of liberal eugenics state that parents that force their child to practice piano for hours each day also exert control over the life of a child, one that can never be reciprocated. In other words, whether a child is free to choose their own plan is undermined by parental intervention, whether it is eugenic or natural.


The eugenic goal of enhancing our children may be well-intentioned, but in the process, it confuses improving our children’s quality of life with robbing them of their humanity. As we have seen, the unforeseen and unintended consequences of genetic enhancement are complex and profound. Efforts to genetically enhance traits such as intelligence blur the line between nature and technology. Respect for nature as we find it means that it must slowly evolve according to its natural process. 

Genetic enhancement of embryos is at present, not possible and perhaps even science fiction. However, given the rapid pace of technological advancements, critics and opponents propose that it be banned now, before it can ever actually come to flourish as a reality. A more realistic recommendation, however, is that such a ban be temporary in nature, during which time an international consensus would be developed to legislate a full range of regulations and enforcement procedures pertaining to all modes of genetic engineering.

The benefits of fully understanding the human genome are insurmountable. It further allows us to understanding the nature of life.  Studying the genetic makeup of sick and healthy people enables geneticists to find the cures for diseases based on the observed differences.  Genomic study allows us to identify genetic predisposition to certain diseases which in turn allows medical practitioners to intervene as early as possible with preventive treatment. Altering the genetic composition of disease-prone individuals to prevent them from realizing certain inherited diseases is clearly beneficial.  How can it be argued that these outcomes do not pose favorable advancements to society? The challenge of welcoming technological advances is that they inevitably yield discoveries that enable mankind to accomplish feats far beyond what can be deemed beneficial to humanity. Genetic enhancement is naturally the next logical course in the development of the field of genetic engineering. And therein lies the moral quandary. Ethical dilemmas are born out of technological advancements and this one is no different. By enhancing the genetic makeup of the human species, we are undermining the individuality of humans. The recommendation of this paper is the only plausible one – the world needs to collectively pause and reflect on what is at stake. While ethical discourse should not impede technological progress, it is important to ensure that further refinement and thoughtful evaluation of the negative repercussions of gene enhancement be fully understood. Otherwise, mankind will find itself crossing a line not meant to be crossed.


In an announcement on this date, a team of British and American scientists announced that they have discovered 52 genes linked to intelligence, 40 of which are entirely new genetic identifications. The team’s discovery was made by merging data from 13 earlier studies in order to form a database of genetic markers and intelligence test scores large enough to produce statistically compelling evidence that certain genes are linked to human intelligence.

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