Another world is not only possible, she is on her way. On a quiet day, I can hear her breathing. – Arundhati Roy

Humanity has a habit of creating swords for itself. Some of them — like the burning of oil — started out with a single edge proudly facing outwards before revealing their second edge as we learned things. Others — such as the splitting of atoms — have been the reverse, with an inward-facing edge nearly chopping us in half before we managed to discover a second edge. All technological and scientific developments can be thought of in this way. They can harm us and they can benefit us; the challenge is to minimize harm while maximizing benefit.

There’s a sword being created called human genetic enhancements. Now, you may think that human genetic enhancement is a far off technology, barricaded by regulatory hurdles, and that it’s almost irrelevant to our generation. With regard to directly editing human genes by snipping them up and changing them, you would be correct, but there’s another way of going about it which has already hopped regulatory hurdles and is being used — it goes by the name of pre-implantation genetic screening. The idea is simple: combine some sperm and an egg, read the genome of the resulting embryo, repeat for a couple dozen embryos, then pick the embryo with the best-looking genome and implant it in the mother. Voilà, you have genetically enhanced a human. Well actually, you have genetically selected a human; you have genetically enhanced them only if you picked the right embryo. So far, we only know enough about genes to discard embryos with obvious gene-related diseases (how pre-implantation genetic screening has been used so far), and we don’t yet have enough knowledge to select for things like intelligence. However, with the recently plummeted cost of full genome sequencing and our newfound ability to extract information from massive amounts of genetic data, studies about the relation between our genes and complex traits like intelligence are starting to bear fruit. In other words, we are starting to know what genes to screen for if we want to get smarter — and we already know how to do the screening.

I say we “already know how”, but there are remaining technical challenges with preimplantation genetic screening. The DNA in cells isn’t like a book in a bookshelf: it’s not possible to pull out the DNA from an embryo’s cell, read it, and neatly tuck it back in. In preimplantation genetic screening, the current practice is to invasively remove cells from young embryos to get their genetic information, and we’re not entirely sure about the long-term harm of doing this. On top of this, current preimplantation genetic screening methods are expensive, and there are epigenetic (gene expression) risks associated with the in-vitro fertilization process. However, the technology is still fairly new, and given its potential value, it’s not farfetched to expect the kinks to be resolved soon. Progress is underway as I write; for example, scientists have recently been developing techniques to sequence the genome of embryos without removing cells, by sampling free-floating DNA from the liquid in and around embryos. Technical breakthoughs of this sort would decrease the cost and risk of preimplantation genetic screening, clearing the path for widespread use.

Now that we have an idea of the sword we’re talking about, lets check its outward-facing edge.

The benefits of human genetic enhancements apply to society as a whole and to our individual experience of life. At the societal level, human genetic enhancements have the potential to significantly improve our economic and scientific productivity, and perhaps enable us to avoid catastrophies, such as runaway climate change. At the individual level, there is the direct benefit of improved quality of life for the enhanced. Nick Bostrom, a philosopher and proponent of human physiological and intellectual enhancement, describes the possibilities that exist:

Our own current mode of being spans but a minute subspace of what is possible or permitted by the physical constraints of the universe. It is not farfetched to suppose that there are parts of this larger space that represent extremely valuable ways of living, feeling, and thinking.

Our ego wants us to think that humans can’t get much better than us. It helps to acknowledge this before contemplating the possibilities. It also helps to critically examine human traits. Consider the mental traits that served a purpose for hunters and gatherers, but that no longer serve a purpose and are now detrimental — for example, our capability for barbaric violence. You may think that the Germans who massacred Jews or the Rwandans who massacred Tutsis are somehow different than us — that there is no way we would commit such acts — but the sad reality is that we have the same biology, and given exposure to the same environment (life experience, etc.), any of us could very well have commited the same atrocities. This aspect of human nature is one of many that are disatisfying and for which riddance could be morally justified.

Now, how about the inward-facing edge?

Opponents to human genetic enhancements have warned that we might inadvertently eliminate valuable human traits. For example, if we genetically select to reduce our tendency for violence, we might unintentionally reduce our tendency for innovation (genetics can be bizarre in this way). One could argue that this isn’t a flaw in human genetic enhancements, but a flaw in our understanding of how to do the enhancements, and that we may eventually have enough knowledge about genes for there to be practically no inadvertent consequences. This hoped-for level of knowledge is overly idealist, at least in the near future, but it cannot be dismissed as unattainable.

Another concern is loss of beneficial genetic diversity. With the natural approach to procreation, genetic experiments are imposed by the randomness of nature. But will people want to experiment if they have the option not to? It’s possible that the use of genetic selection would deny existence to many desireable genetic outliers. If Einstein’s parents knew his genome while he was in a petri dish and were less sure of him being a functional human compared to a sibling embryo, perhaps we’d still be clueless about spacetime¹.

Beyond questions of human diversity and of the reliability of our genetic understanding, issues of individual liberties arise. Should parents be allowed to select the genes of their children with the children unable to give consent? In the modern world, governments can only interfere with how children are raised when it avoids significant, predictable harm. For example, one cannot denny their children from going to school or give them an embarrassing name. However, parents have the freedom to inflict harm to their children in numerous ways, but they are trusted not to because parents generally have the best interests of their children in mind. We could take a similarly moderate approach to regulating what genetic selections parents would be allowed to make by banning selections that risk being harmful while allowing selections that are predictably beneficial.

Now here’s where the sword gets sharp. If some countries allow genetic enhancements while others don’t, the term human species will regain its plural sense; society will branch into genetically stratified tiers. Based on historical trends, this would lead to violence and suffering. The only way to avoid genetic branching is by making sure everyone is on the same page about what is acceptable and what isn’t, and by making the genetic enhancements that are allowed universally available throughout the world’s population, so that everyone remains as genetically similar as possible. The extent of what is allowed can range from no genetic enhancements (banned) to the technical limits of what we know how to do.

At this point, I should make a distinction: There is genetic selection for enhancement and genetic selection for therapy. Enhancement is improvement beyond the norm, and therapy is restoration to the norm. Up to now, I’ve focused on genetic enhancements, but much of the above applies to both. Also, it’s worth noting that the line between the two is blurry. For example, is reducing the probability of mental health issues therapy or enhancement? And is reducing the probability of old-age diseases — and thereby extending lifetime — therapy or enhancement? Despite the blurriness of the line, the distinction is useful because genetic selection for enhancement and genetic selection for therapy occupy different ethical realms, and as a result, regulations treat them very differently.

Preimplantation genetic screening for therapy is already allowed in many countries and even encouraged in some. If adoption increases and current regulatory attitudes are maintained, we will lose the option of universally banning genetic selection for therapy. The logical next step will be to minimize harm by making the procedures that are allowed as available as possible to everyone. This may require a sort of international, universal health care system that provides preimplantation genetic screening services. However, the pressure for universalization comes predominantly from genetic selection for enhancement because intellectual differences are linked to wealth and power, and physical differences create falsely perceived differences, hence racism². Preimplantation genetic screening for enhancement is generally banned as of this writing, and this is largely due to it being ethically questionable, but generally is not enough — to prevent genetic stratification, regulations must be the same everywhere.

In theory, the solutions of universal banning or adoption sound clever, but in practice, massive international coordination about controversial topics doesn’t happen easily. If even just one country bans or allows genetic selection against the consensus, branching is guarranteed. As Hank Greely, director of the Center for Law and the Biosciences at Stanford, put it, “There are roughly 200 countries in the world. If 199 ban it, that’s a great commercial opportunity for the 200th”. Ideally, action will be either unanimous or imposed with international law.

Nonetheless, we have practical conclusions: humanity should decide the extent of allowable genetic selections (both for therapy and enhancement), make those that are accepted universally available, and enforce the ban on those that aren’t. The easiest time to implement global rules on genetic selections is before the technology matures and before an elite genetic class starts taking shape. It follows that there’s an urgent need for conversation about what should be banned and what should be allowed, and for collective action to prevent genetic stratification of our society.

Humanity faces few challenges of comparable importance as that of how we will handle our ability to modify ourselves. How we learn to deal with this newfound power will have massive consequences for the likely trillions of future human lives. Until the challenge is overcome, disagreement is to be expected, as one would expect for the topic of fundamental changes to who we are. What is crucial is that we enliven the back-and-forth because the reality is that a sword is in the forge.