The Good Ones into the Pot

May we breed humans? And if so, how? More beautiful, taller, more intelligent? Should it be a life without diseases or, even better, an eternal one? In this respect, Peter Sloterdijk is right: the topic has been discussed since Plato. In the third book of his Politeia, the Greek philosopher poses the rhetorical question of how men and women should pair. The answer: "The best with the best and the worst with the worst." It should be mentioned, however, that Plato's fame is not exactly based on contributions to natural science; those were later provided by his student Aristotle, in opposition to Platonic doctrine.

Even without Plato's advice, humanity has not reproduced randomly. Families, village communities, tribes, and clans have produced certain types, such as red-haired Vikings. The marriage policy of European royal houses was also an attempt to keep noble blood noble. However, one effect was certainly not desired, which occurs in every breeding process: breeding inevitably means inbreeding. The best may pair with the best, but in the end, something bad may come out of it. Centuries of cousin marriages have rather genetically sidelined Europe's high nobility. The Habsburg dynasty, for instance, developed the Habsburg lip, a jaw deformity that forced those affected to primarily consume soup or porridge. The Romanov lineage was marked by hemophilia; Russia's last Tsarevich suffered from this blood disease, as did Queen Victoria.

Two thousand years after Plato, more than 100 years after Johann Gregor Mendel, one might think humanity is smarter. On the one hand, concerning the erroneous path of racist eugenics. On the other hand, regarding the "royal knowledge of breeding" that Sloterdijk addresses. Are we really capable today of improving the human species? More simply asked: What technology is available? And what can we do with it? Strictly excluding ethical concerns, the answer is: a lot.

The progress, if it is one, comes from medicine and genetic engineering. Both disciplines unite where desperate prospective parents seek help—in reproductive medicine centers. In vitro fertilization is now the standard method when the desire for children is unfulfilled. And care is provided for the time after conception. From conception to birth, doctors accompany mother and child. At various stages of pregnancy, the genetic material of the unborn child can be analyzed. The triple test (for Down syndrome) or the cystic fibrosis test are two of the most common. About 100 new DNA tests come onto the market annually. 800 genetic diseases can be diagnosed, and science knows about 5,000 other gene sequences that are associated with various diseases.

Virtually none of these diseases can be causally treated. Only a few are treatable. In case of doubt, a negative decision is made; abortion is the only way to prevent a genetically diseased child. All the mentioned test methods also have the disadvantage of providing reliable results late—some only after the 20th week of pregnancy. At this point, a fetus would already have a chance of survival outside the womb.

Those who fear nothing more than a genetically diseased child face a dilemma. The choice is between abstaining from offspring or a trial pregnancy (with the option of abortion)—this was the alternative until recently. The term eugenics is reluctantly used in this context; it is said that the participants make an individual decision, according to their own conscience and after thorough consultation.

Of course, every couple is free to bring a disabled child into the world, knowing this. However, this will probably soon become the exception due to comprehensive diagnosis. On the contrary, a societal climate is conceivable that subtly discriminates against genetic diseases because "such a thing" should really no longer exist in light of medical knowledge. In other words: no Platonic shepherd of men, but also no Hitlerian villain is needed to put the eugenic idea into practice. Concerned parents are sufficient. The rest may be taken care of by kindergarten, school, and a social environment that no longer views an unfortunate genetic fate as God-given but as self-inflicted in the future.

Every person carries around half a dozen genetic diseases

At this point, an objection is due. The idea that one could create a "genetically healthy society" through the back door in this way is flawed. Only very few diseases are inherited dominantly (dominant means that just one gene copy, whether from the father or the mother, alone triggers the disease). Almost always, two defective gene copies must come together (a process called recessive inheritance). This is unlikely in people who are not blood relatives. Accordingly, genetic diseases are generally rare; in some cases, the number of experts researching them far exceeds the number of patients suffering from them.

Genetic diseases, therefore, remain hidden. In fact, they are hidden in all of us, who make up an estimated 98 percent of humanity that appears healthy. Each of us carries around an average of half a dozen rare genetic diseases. However, they would only come into play if we found a partner who happened to have the same predispositions. This is known as the Hardy-Weinberg principle, named after its two discoverers: Rare recessive traits are like a needle in a haystack. Anyone who truly wants to eradicate a recessive genetic disease would have to screen 98 percent of the population (and potentially prevent them from reproducing) in which it is currently not manifesting. Such mass screening is hardly feasible; its effort would be disproportionate to the intended result.

Conclusion: Negative eugenics is possible. It is already being practiced in individual cases. It could eventually reshape morals and society, but not the human genetic material in its entirety.

Philosophers have always aimed for more. Even Plato or Nietzsche did not just dream of eradicating the weak or sick. They wanted to improve humanity as such. Is such positive eugenics possible with today's knowledge? At first glance, no. For this, one would have to be able to transplant human genes somewhat precisely. The technique has already been tested. There have been about 100 clinical trials on more than 600 patients, targeting diseases like lung cancer, muscular dystrophy, or familial hypercholesterolemia using gene therapy to tackle them at their root. According to theory, a defective gene in the body is supposed to be replaced by a functioning one. In practice, all experiments have failed so far. Which does not mean that this will remain so forever. Laboratory mice can now be manipulated almost at will over generations.

Similar procedures as in somatic gene therapy would also have to be used in any possible germline therapy (intervention in sperm and egg cells). Attempts at human germline therapy are currently globally condemned and even banned in many countries. The same applies to the deliberate cloning of humans. Cloning would at least be a conceivable way of positive eugenics, as the expected result can, at least roughly, be inspected during the lifetime.

"Superhumans" they would still not be. At most, copies of humans who consider themselves particularly successful (or are so in the eyes of others). However, the vast majority have little interest in this. Prosaically speaking, most parents only wish for their offspring to be a bit smarter, a bit more beautiful, or perhaps a bit more musical; in other words, that they will have it a bit better. If science were first able to fulfill this wish, it would not be hard to imagine the corresponding demand.

The imagination is certainly heated. For years, hardly a month has passed without a new intelligence gene, a gene for this or that being introduced. It must be noted: even the habit of picking one's nose can easily be linked to the presence of certain gene segments, just as the decline in birth rates can be casually explained by the extinction of the stork: Hardly any scientific field moves in such murky waters as the genetics of human behavior.

The reason for this is again of a technical nature. Even the fewest diseases can be clearly assigned to a single gene; usually, dozens are involved. Conversely, dozens of different genes can cause the same disease. Furthermore, a gene by itself does nothing; it is controlled by other genes, all of which together are part of an entire cascade of biochemical processes that are often feedback-regulated. Finally, the reaction of an organism depends crucially on environmental influences. Even the absence of environmental influences is an environmental influence.

No one is thinking of a superhuman - the raw material for that simply doesn't exist

The study of individual genes that influence the behavior of animals and humans can thus only contribute a small part to understanding. And certainly not provide the raw material for superhumans. Serious behavioral geneticists know this; in their publications, they usually specify which statistical methods they used to arrive at their results. Behaviors are complex, even more complex than diseases, and when it comes to studying complex things, statistics are the only way out. Thus, one should not seriously expect to be able to one day place a cuddly genius gene in one's offspring's cradle. The human genome and human nature are not so simply structured.

Does this mean that positive eugenics, in the sense of Plato or Nietzsche, will remain fantasy forever? No. If one bids farewell to pipe dreams, then a very real possibility remains. It carries the unwieldy name preimplantation genetic diagnosis (PGD). This is the latest trick from the reproductive medicine toolkit. Couples who, for example, decide on artificial insemination due to high risk are already offered the PGD service in Belgium or Great Britain. In this process, several fertilized eggs are cultivated in a petri dish. In an early stage of division, when the individual embryos consist of no more than twelve cells, one or two cells are removed from each. Their genetic material is then chemically amplified. In this way, the genetic constitution of a potential offspring can be determined before it is on its way to the uterus. And it is at this very moment that a consequential decision is due. This embryo shall become a human, that one shall not. No matter what you call it—it is a step toward selection.