This blog post explores the impact of designer humans and genetic manipulation technologies on human evolution and diversity. We examine the future changes that advancements in science and technology may bring.
The recent global decline in biodiversity has become a serious problem. This issue could have significant implications not only for the environment but also for humanity’s future viability. According to a report by the International Union for Conservation of Nature (IUCN), the decline in species is ranked among the most urgent environmental problems we currently face. The diverse species on Earth are essential for maintaining the balance of ecosystems, and if this balance is disrupted, the repercussions can ripple throughout the entire ecosystem. For example, the extinction of a specific species can lead to the collapse of the food chain, threatening the survival of other species that interact with it.
According to a series of articles in The Science Times, the number of species on Earth is currently estimated to be between 13 million and 14 million. Among these, 25,000 to 50,000 species are disappearing each year due to development and pollution. Particularly, species extinction in regions with high biodiversity, such as tropical rainforests, is emerging as an even more serious problem. These areas are home to more than half of the Earth’s species, and a reduction in species occurring here could have a profound impact on ecosystems worldwide. Experts warn that if this trend continues, 25% of all species on Earth could become extinct within the next 20 to 30 years.
The decline in biodiversity is not merely about a reduction in the number of species. It can lead to a decrease in the resilience of ecosystems, which in turn signifies the collapse of ecosystem services. Ecosystem services refer to the benefits humans derive from nature, including clean water and air, food supply, and climate regulation. Therefore, the loss of biodiversity can destabilize these essential services, directly impacting human life.
Human-induced disturbances to ecosystems have mostly resulted in catastrophic consequences. During China’s Great Leap Forward, Mao Zedong’s declaration that “sparrows are harmful birds” led to the mass extermination of sparrows, resulting in the tragic death of tens of millions from starvation. As sparrow populations plummeted, the pests they preyed upon proliferated, devastating grain production. This serves as a stark example of how catastrophic the consequences can be when humans intervene in nature without sufficient consideration and research. Australia experienced a similar case: twelve rabbits introduced in the mid-1800s multiplied to 10 billion within 60 years, devastating the entire nation. Thus, human-intended alterations to planned ecosystems mostly lead to negative outcomes. Sometimes the impact isn’t immediately felt; it may manifest decades or even centuries later. Moreover, even when the problem is identified, restoring the original state is often extremely difficult.
However, advances in genetics have created an environment where humans themselves can shake the very direction of the future evolution of the human species. Consequently, the issue of reduced diversity may no longer be solely a problem for species other than humanity. While gene-editing technology has positive applications like disease treatment, it could also profoundly impact humanity’s natural evolutionary process. This can be interpreted as a challenge to the genetic diversity of humanity as a whole, extending far beyond individual health issues.
One of the core technologies in genetics is the decoding and manipulation of DNA. When the human genome map was completed in 2001, Francis Collins, Director of the National Institutes of Health, stated, “Using the genome map, we could create genetically engineered humans by 2020.” As of 2025, researchers indicate that decoding the human genome is not progressing as rapidly as previously anticipated, but the prevailing view is that genetically modified humans will eventually be born. While such genetic modification would be ideal if used for positive purposes like curing incurable diseases or criminal investigations, it could become a major problem if employed to create humans tailored for specific purposes. Ethical debates persist, particularly regarding the risk that genetic engineering could exacerbate social inequality or become a technology accessible only to privileged classes.
The film ‘Gattaca’ (1997) serves as a cautionary tale against humanity’s optimistic expectations for the advancement of genetics. Before birth, genetic engineering ensures children inherit only the traits their parents desire. These individuals are ‘qualified’ as custom-made humans. All others are ‘unqualified’ natural humans. The film’s plot centers on protagonist Vincent, born into the ‘unqualified’ class, striving to achieve his dream of becoming an astronaut. While the film’s central lesson is important, here we focus on a conversation Vincent’s parents had with a doctor at the hospital before conceiving his younger brother, Anton. Vincent’s parents preemptively controlled factors like Anton’s gender, presence of diseases, physical appearance, personality, and likelihood of obesity to give their child the optimal conditions for societal success. Considering the film’s scientific context, the use of the term “elimination” suggests they are removing genetic factors deemed socially disadvantageous before birth. This effectively reduces the number of genetic traits passed from parents to offspring.
While this might seem unproblematic, it has the potential to cause serious damage to genetic diversity. Genetic diversity, along with beneficial mutations, is an essential element for the evolutionary adaptation of organisms. A reduction in genetic diversity inevitably makes organisms vulnerable to new environments, meaning even minor environmental changes could potentially lead to the mass extinction of the species itself. If genetics were as advanced as depicted in the film, one might think such problems would already be solved. However, while science and technology themselves are value-neutral, the people who use them are not. Therefore, this problem cannot be viewed optimistically. Let’s assume, though it seems almost impossible, that a society has been achieved where wealth inequality and even the genetic-based class conflicts depicted in movies have been completely eradicated. How genetically diverse would the humans in such a society be? They would possess at least less genetic diversity than we do today.
For such an evolved humanity, we might need to worry about human extinction not only from major external changes imaginable today, like new diseases or shifts in Earth’s climate, but also from unimaginably minor changes. The loss of biological diversity could impact not just ecosystems but human society as a whole, becoming particularly pronounced during unexpected crises. One of the primary reasons inbreeding is prohibited today relates to genetic diversity. The consequences of inbreeding to preserve the purity of European royal bloodlines are already well-known. Furthermore, science is not a magic wand capable of solving everything. The notion that human imagination has no limits implies, conversely, that there will always be something we haven’t thought of. A reduction in human genetic diversity could make it difficult to respond to and adapt for ‘completely unforeseen situations’.
Of course, genetic manipulation at the birth stage may not necessarily lead solely to a reduction in human genetic diversity. If genetics advances further to the point where socially desirable traits can be created through genetic manipulation, then the existing, declining genetic traits could be replaced with new, human-created genetic traits, potentially increasing diversity instead. Just as humans of the past differed from humans today, humans of the future could possess even greater diversity than we see now. However, this scenario carries the problem that recessive genetic traits deemed no longer necessary could be eliminated again, making a significant increase in the total quantity of genetic traits unlikely. Rather, artificial intervention in genetic traits accumulated over hundreds of thousands of years will likely cause the total quantity of human genetic traits to steadily decrease, contrary to outward appearances. Furthermore, the possibility of speciation occurring—leading to the emergence of a new species nearly identical to humans but incapable of reproduction with them—cannot be ruled out. Ultimately, in any scenario, genetic manipulation could pose a significant threat to human survival rather than aiding it.
However, many argue that ‘custom-made humans’ are necessary because the advantages of such individuals outweigh the disadvantages. A prominent argument is that genetic manipulation could help achieve an equal world where all humans start life on a fair playing field. This argument states that while genetic modification technology may appear immoral at first glance—judging humans based on factors beyond their control and thus causing unreasonable discrimination—it is actually an innovative technology that acknowledges human genetic differences and provides an opportunity for fairer competition. Therefore, it claims we can enter an equal world free of disabilities or diseases through genetic modification technology.
However, even if disabilities or diseases initially help create a level playing field, can an equal world truly be achieved solely through laws, systems, or human perception? Evaluating humans based on factors unrelated to effort, if it hinders fair competition among people, would require equalizing not just diseases and disabilities but all other non-effort-related external factors to complete an equal world. Yet since time immemorial, humanity has always lived amidst the rifts of conflict and division. Perfect equality, excluding effort, has never been achieved under any circumstances. If one factor becomes equally possessed by all, evaluation begins based on another factor. Genetic manipulation solely to eliminate disease and disability could be dangerous. Factors for discrimination like height, intelligence, and skin color would constantly emerge. Restricting these evaluation factors through laws, systems, and education will also prove difficult. Regulation always lags one step behind societal change.
Paradoxically, all the inequalities inherent in humanity can be seen as the driving force behind human progress. Humans have always strived to move toward overcoming inequality. Human history can be described as the ongoing effort to share power and wealth concentrated in the hands of a few. Even without actual warfare involving guns and swords, the world is perpetually engaged in an invisible war. Through such conflicts, humanity has naturally learned lessons over millennia, pursued more universal values, and acquired them—this is what we have done and will continue to do. Indeed, the moment absolute equality is achieved, human progress might very well cease. Genetic manipulation cannot be used to create an equal society. This is because the world is always composed of diverse people with diverse thoughts.
All 7 billion humans on Earth possess different genetic characteristics. There is no such thing as a perfectly 100% identical human being. This can be considered a blessing for humanity. The formation of human self-identity involves establishing one’s own values by observing others who are different from oneself. Amidst countless people different from themselves, each human being lives to leave behind evidence of their existence in the world: by having children, writing words, and holding dreams and hopes in their hearts. This ‘natural human’ should not be altered into a ‘custom-made human’ for the sake of creating a better society.
A society where human diversity is lost can be called a dead society. In Suzuki Koji’s novel ‘Ring’, the loop—another world implemented within a computer—lost its diversity as Yamamura Sadako, genetically identical, multiplied infinitely. This world ultimately becomes boring and unchanging, a perfectly frozen world with no further evolution or development. This may be an overly extreme example. However, the emergence of ‘custom-made humans’ must not be dismissed as an insignificant factor. It could become a major cause of reduced human diversity, posing a significant threat to the challenge of humanity’s continued development and prosperity. In short, the loss of diversity through genetics is a profoundly serious issue. On a small scale, it can lead to the loss of individual uniqueness and the stagnation of societal progress. On a larger scale, it could threaten the very preservation of the human species itself.
