In this blog post, I will examine the differences between engineered humans and natural humans as depicted in the movie ‘Gattaca’ and attempt to refute the arguments in favor of engineered humans.

Problems Arising from Reduced Genetic Diversity

The movie “Gattaca” is set in a future society where scientific and technological advancements have made it possible to freely manipulate genes. As a result, humanity is divided into two groups: “natural humans,” who are born without genetic modification, and “designer humans,” who are born with superior traits through genetic engineering. In the film, the protagonist Vincent is a natural human, while his younger brother Anton is a designer human born with superior traits. Vincent applies to a company called “Gattaca” in pursuit of his dream of becoming an astronaut. However, because he is not a “custom-made human,” he is rejected. While working as a janitor at Gattaca, Vincent meets another protagonist, Jerome, through a DNA broker. Since Jerome is a “custom-made human,” Vincent devises a plan to become an astronaut by using Jerome’s DNA. While carrying out his plan, he nearly has his true identity exposed several times and experiences conflict with Jerome, but in the end, Vincent becomes an astronaut and departs for Saturn. This raises a question: Are genetically engineered humans unconditionally better than naturally born humans? Genetically engineered humans would certainly find life more convenient than naturally born humans. However, it is difficult to believe that a society where everyone is genetically engineered would be better than our current society of naturally born humans.

What are the problems with the arguments in favor of “custom-made humans”?

In this article, I will attempt to refute the arguments in favor of “custom-made humans.” In his essay, Kim Ji-hoon argued that the advantages of “custom-made humans” include an improved quality of life for humans and that genetic diversity would not be reduced in the process. He also argued that discrimination between customized humans and natural humans can be prevented by law, and that there are no ethical issues because the process involves ensuring the fetus is born healthy.
There are several problems with these arguments. Even if discrimination between customized humans and natural humans is prevented by law, companies will continue to devise new methods to select superior customized humans. Furthermore, regarding ethical concerns, if it becomes possible to manipulate genes at will, parents might resort to illegal methods to obtain better genes, and children would be born with altered genes based on their parents’ will rather than their own. Aside from these issues, I believe the most significant problem is the reduction in genetic diversity, which I will discuss below.

Will genetic diversity decrease as the number of “custom-made humans” increases?

First, regarding the process of creating “custom-made humans,” Kim Ji-hoon’s article states that genetic diversity does not decrease. Creating “custom-made humans” involves removing recessive genes, and when recessive genes are removed, the number of genes decreases accordingly. In other words, genetic diversity decreases. One might argue that since only recessive alleles are removed from the parents’ genes, the total number of genes is not significantly reduced. However, because the range of diseases humans can contract is so vast, viewed from the perspective of humanity as a whole, the number of genes lost with each generation is actually quite large. Furthermore, in a situation where genes can be freely manipulated, parents will likely want to pass on the “best” genes to their children. Since the types of “good” genes are limited, people’s genes will become increasingly similar over the course of a few generations.
If this situation repeats itself, the number of genes will decrease significantly within just a few generations. Opponents of this view might counter as follows: For example, some parents might pass on genes for extreme height to their children in the hope that they’ll become basketball players, while others might pass on genes for short stature in the hope that their children will become equestrians. Furthermore, some parents might even pass on genes for unattractive facial features to their children in the hope that they’ll become comedians. However, it’s safe to say that the diversity resulting from this is negligible. This is because most people would prefer a moderate height rather than an extreme one, and would prefer children with handsome faces—like those of Kang Dong-won or Won Bin—rather than unattractive ones. Thus, a reduction in genetic diversity is inevitable, and this leads to many problems.

What problems arise when genetic diversity decreases?

The most significant problems resulting from a decline in genetic diversity include a weakened ability to adapt to changes in the natural environment and reduced resistance to disease. If the natural environment were to change from what it is today, most genetically engineered humans—whose genes are so similar—would struggle to survive. Furthermore, if a new virus—one not yet discovered—were to emerge, it could result in a very high number of casualties. Historically, there have already been diseases that caused massive casualties, such as the Black Death and the Spanish Flu. One might think that since disease-related genes are completely removed when creating genetically engineered humans, they would be less susceptible to disease, but this is a misconception. If a new virus were to cause a new disease, everyone except those immune to it would become infected; if such an event occurred in a situation where most people’s genes are highly similar, it could lead to the extinction of humanity. One might argue that if science and technology have advanced to the point of genetic manipulation, diseases could be easily cured, but I believe there is insufficient evidence to support this claim. The science of treating diseases and the science of genetics are clearly distinct, and even if we were to search for a cure for a new disease, countless people would die in the meantime.

Is a “natural human” a better choice than a “designer human”?

This is not to say that designer humans are bad. If designer humans were to emerge, the quality of life in society would certainly improve, and a society led by people with superior abilities would develop more rapidly. However, it is highly likely that solving the problems that could arise in a society of designer humans would be more difficult than living as natural humans today. Therefore, I believe that living as a natural human is also a perfectly good choice.