This year's 50th anniversary of the discovery of the structure of DNA has kindled many debates about the implications of that knowledge for the human condition. Arguably the most emotionally charged is the debate over the prospect of human genetic enhancement or "designer babies". It's only a matter of time, many say, before parents will improve their children's intelligence and personality by having suitable genes inserted into them shortly after conception.
A few commentators have welcomed genetic enhancement as just the latest step in the struggle to improve human life. Many more are appalled. They warn that it is a Faustian grab at divine powers that will never be used wisely by us mortals. They worry that it will spawn the ultimate inequality, a genetic caste system. In his book Our Posthuman Future (just released in paperback), the conservative thinker Francis Fukuyama warns that genetic enhancement will change human nature itself and corrode the notion of a common humanity that undergirds the social order. Bill McKibben, writing from the political left, raises similar concerns in his new jeremiad Enough: Staying Human in an Engineered Age.
Whether they welcome or decry it, almost everyone agrees that genetic enhancement is inevitable if research proceeds on its current course. In America, genetic enhancement is a major concern of the president's Council on Bioethics; its chairman, Leon Kass, and several of its members, including Fukuyama, are outspoken worriers.
As it happens, some kinds of genetic enhancement are already here. 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. And it is already possible to test embryos conceived in vitro and select ones that are free of genetic defects such as cystic fibrosis.
But when it comes to direct genetic enhancement - engineering babies with genes for desirable traits - there are many reasons to be sceptical. Not only is genetic enhancement not inevitable, but it is not particularly likely in our lifetimes. This skepticism comes from three sources: the limits of futurology, the science of behavioural genetics, and human nature itself.
The history of the future should make us raise an eyebrow whenever the experts tell us how we will live 10, 20, or 50 years from now. Not long ago we were assured that by the turn of the century we would live in domed cities, commute by jet-pack, and clean our homes with nuclear-powered vacuum cleaners wielded by robot maids. More recently we were promised the paperless office, interactive television, the internet refrigerator, and the end of bricks-and-mortar retail. It's not just that these developments have not yet happened, many of them, like domed cities, never will happen. Even in mun dane cases, technological progress is far from inexorable. Air travel, for example, is barely faster or more comfortable today than it was when commercial jets were introduced 50 years ago.
Why are technological predictions usually wrong? Many futurologists write as if current progress can be extrapolated indefinitely - the fallacy of climbing trees to get to the moon. They routinely underestimate the number of things that have to go right for a development to change our lives. It takes more than a single eureka!; it takes a large number of more boring discoveries, together with the psychological and sociological imponder-ables that make people adopt some invention en masse. Who could have predicted the videophones of the 1960s would sink like a stone while the text messaging of the 1990s would become a teenage craze?
Finally, futurologists tend to focus their fantasies on the benefits of a new technology, whereas actual users weigh both the benefits and the costs. Do you really want to install software upgrades on your refrigerator or reboot it when it crashes?
Many prognosticators assume that we are in the midst of discovering genes for talents such as mathematical giftedness, musical talent and athletic prowess. The reality is very different. The achilles heel of genetic enhancement will be the rarity of single genes with consistent beneficial effects.
Behavioural genetics has uncovered a paradox. We know that tens of thousands of genes working together have a large effect on the mind. Twin studies show that identical twins (who share all their genes) are more similar than fraternal twins (who share half their genes, among those that vary from person to person), who in turn are more similar than adopted siblings (who share even fewer of the varying genes). Adoption studies show that children tend to resemble their biological relatives in personality and intelligence more than they resemble their adopted relatives.
But these are effects of sharing an entire genome, or half of one. The effects of a single gene are much harder to show. Geneticists have failed to find single genes that consistently cause schizophrenia, autism or manic-depressive disorder, even though there is overwhelming evidence that these conditions are substantially heritable. And if we can't find a gene for schizophrenia, we're even less likely to find one for humour, musical talent, or likeability, because it's easier to disrupt a complex system with a single defective part than to improve it by adding a single beneficial one. The 1998 report of a gene that was correlated with a four-point advantage in IQ was recently withdrawn because it did not replicate in a larger sample - a common fate for putative single gene discoveries.
S o don't hold your breath for the literary creativity gene or the musical talent gene. The human brain is not a bag of traits with one gene for each trait. Neural development is a staggeringly complex process guided by many genes interacting in feedback loops. The effect of one gene and the effect of a second gene don't produce the sum of their effects when they're simultaneously present. The pattern of expression of genes (when they are turned on or off by proteins and other signals) is as important as which genes are present.
Even when genes should be at their most predictable - in identical twins, who share all their genes, and hence all the interactions among their genes -we don't have foregone conclusions. Identical twins reared together (who share not only their genes but most of their environments) are imperfectly correlated in personality measures such as extroversion and neuroticism. The correlations, to be sure, are much larger than those for fraternal twins or unrelated people, but they are seldom greater than 50%. This tells us there is an enormous role for chance in the development of a human being.
It gets worse. Most genes have multiple effects, and evolution selects the ones that achieve the best compromise among the positive and the negative ones. Take the most famous candidate for genetic enhancement: the mice that were given extra copies of the NMDA receptor, which is critical to learning and memory. These poster mice did learn mazes more quickly, but they also turned out to be hypersensitive to pain. Closer to home, there is a candidate gene in humans that appears to be correlated with a 10-point boost in IQ. But it is also associated with a 10% chance of developing torsion dystonia, which can confine the sufferer to a wheelchair with uncontrollable muscle spasms.
This places steep ethical impediments to research on human enhance ment. Even if some day it might be possible, could you get there from here? How can scientists try out different genes to enhance the minds of babies given that many of them could have terrible side effects?
Genetic enhancement faces another problem: most traits are desirable at intermediate values. Wallis Simpson said that you can't be too rich or too thin, but other traits don't work that way. Take aggressiveness. Parents don't want their children to be punching bags or doormats, but they also don't want Attila the Hun either. Most want their children to face life with confidence rather than sitting at home cowering in fear, but they don't want a reckless daredevil out of Jackass. So even if a gene had some consistent effect, whether the effect was desirable would depend on what the other tens of thousands of genes in that child were doing.
The third obstacle to re-engineering human nature comes from human nature itself. We are often told that it's only human for parents to give their children every possible advantage. Stereotypical yuppies who play Mozart to their pregnant bellies and bombard their newborns with flash cards would stop at nothing, it is said, to give their children the ultimate head start in life.
But while parents may have a strong desire to help their children, they have an even stronger desire "not to hurt" their children. Playing Mozart may not make a foetus smarter, but it probably won't make it stupider or harm it in other ways. Not so for genetic enhancement. It is not obvious that even the most overinvested parent would accept a small risk of retardation in exchange for a moderate chance of improvement.
Another speed bump from human nature consists of people's intuitions about naturalness and contamination. People believe that living things have an essence that gives them their powers and which can be contaminated by pollutants. These intuitions have been powerful impediments to the acceptance of other technologies. Many people are repelled by genetically modified foods even though they have never been shown to be unsafe or harmful to the environment. If people are repulsed by genetically modified soybeans, would they really welcome genetically modified children?
Finally, anyone who has undergone in-vitro fertilisation knows that it is a decidedly unpleasant procedure, especially in comparison to sex. Infertile couples may choose the procedure as a last resort, and some kooks may choose it to have a child born under a certain astrological sign or for other frivolous reasons. But people who have the choice generally prefer to conceive their children the old-fashioned way.
It is misleading, then, to assume that parents will soon face the question, "Would you opt for a procedure that would give you a happier and more talented child?" When you put it like that, who would say no? The real question will be, "Would you opt for a traumatic and expensive procedure that might give you a slightly happier and more talented child, might give you a less happy, less talented child, might give you a deformed child, and probably would make no difference?" For genetic enhancement to "change human nature" not just a few but billions of people would have to answer yes.
My point is not that genetic enhancement is impossible, just that it is far from inevitable. And that has implications. Some bioethicists have called for impeding, or even criminalising, certain kinds of research in genetics and reproductive medicine, despite their promise of improvement in health and happiness. That is because the research, they say, will inevitably lead to designer babies. If genetic enhancement really were just around the corner, these proposals would have to be taken seriously. But if the prospect is very much in doubt, we can deal with the ethical conundrums if and when they arise. Rather than decrying our posthuman future, thinkers should acknowledge the frailty of technological predictions and should base policy recommendations on likelihoods rather than fantasies.
Steven Pinker is Peter de Florez Professor in the Department of Brain and Cognitive Sciences at MIT, and author of The Blank Slate, which is published in paperback today by Penguin. To order a copy for £7.99 with free UK p&p call the Guardian book service on 0870 066 7979
Remaking Eden: Cloning and Beyond in a Brave New World, Lee Silver, 1998 (Weidenfeld & Nicolson) ISBN: 0297841351
Redesigning Humans, Our Inevitable Genetic Future, Gregory Stock, 2003 (Houghton Mifflin) ISBN: 0618340831
Our Posthuman Future: Consequences of the Biotechnology Revolution, Francis Fukuyama, 2003 (Profile Books) ISBN: 1861974957
Enough: Staying Human in an Engineered Age, Bill McKibben, 2003 (Times Books) ISBN: 0805070966
Q&A: Bill McKibben on Staying Human
Center for Genetics and Society
May 28, 2003, 7:00 PM GMT
In "Enough," you warn against the dangers -- many of them imminent and grave -- of new technologies that will allow us to "redesign" human beings. Realistically, what kind of redesigning are we talking about?
Genetics researchers are continually discovering new traits linked, in part or in whole, to our DNA: IQ, muscle mass, height, sociability, even our inclination to optimism or happiness. Just as they've already done with many other animals, some scientists want to tweak human embryos at an early stage of development to "enhance" these characteristics.
These sound like pretty far-out ideas. Do you believe anyone -- science -- would actually do that? And if they would, isn't that light years away?
Some researchers with real scientific credibility, and real access to large amounts of venture capital, hope to do just this kind of work. Consider, for instance, James Watson, the co-discoverer of the double helix, who this spring celebrates the 50th anniversary of his Nobel-winning paper. Watson -- who was also the first head of the national genome project -- has called for aggressive pursuit of so-called "germline engineering." He urges society to "go for perfection," using our new understanding of genetics to eliminate shyness and to rule out "cold fish." "Who wants an ugly baby?" he asks, adding, "If we could make better human beings by knowing how to add genes, why shouldn't we do it?"
And Watson is far from alone -- top researchers at places like MIT and UCLA have deemed such work not only a good idea, but "inevitable," predicting that within a very few years the children of most people who can afford the technology will be 'enhanced' before birth. "Why not seize this power?" asks Princeton geneticist Lee Silver in his book Remaking Eden. "We control all other aspects of our children's lives and identities through powerful social and environmental influences... On what basis can we reject positive genetic influences on a person's essence when we accept the rights of parents to benefit their children in every other way."
That's an interesting question. What would be wrong with 'improved' children?
This is at the crux of "Enough." Other writers have at least begun to focus on the practical problems: all the things that could go wrong with these technologies, and the fact that they would enshrine the divisions between rich and poor into our very biology. But I've tried also to raise a deeper set of issues: the meaning of a human life will disappear if we make these changes. To understand what I mean, imagine yourself an 'improved' child. Is your intelligence your own? Is your mood your own, or the result of some protein pumped out by your cells in response to a particular stretch of commercial DNA added by your parents before your birth? Would your accomplishments, your hopes, your dreams mean anything in the way we reckon it now in such a world? Or would you be more akin to a robot?
We already try to influence our children in innumerable ways. But part of growing up is dealing with that influence: rebelling against it, finding the parts you want and rejecting the rest. You'd never be able to reject this kind of influence, though; it would be part of every cell in your body. This is the single most radical technology anyone's ever thought of -- and the greatest breach with all that came before.
Can we avoid this world of designer babies without sacrificing necessary medical progress?
Yes, happily. The insights that genetics have provided already have yielded all sorts of useful treatments for real people with real illnesses. So-called "somatic" gene therapy, involving the insertion of better-functioning genes into living individuals to, say, keep their lungs from malfunctioning due to cystic fibrosis, does not raise the kind of existential problems that come from designing people before they're born. Other researchers are hard at work designing drugs that take into account the genetic peculiarities of certain cancers. All this is good and necessary work, part of the world as we know it.
Even controversial ideas like cloning embryos to get stem cells need not be abandoned. But scientists and government regulators need to work out careful protocols before they proceed in order to insure that cloning embryos for spare cells doesn't turn into reproductive cloning, which would be the basis for making designer children.
Is it just genetics that worries you, or are there other methods of engineering humans on the horizon?
The DNA revolution is on top of us -- people are already claiming to have cloned children. But if you look a few years further out, other technologies are rapidly converging. Roboticists insist, with some credibility, that their creations will be smarter and more able than humans in a few decades; at best, they say, we will need to make ourselves part silicon to survive. "Those of us alive today, over the course of our lifetimes, will morph ourselves into machines," says MIT's Rodney Brooks. "Biological species almost never survive encounters with superior species," adds Carnegie Mellon's Hans Moravec.
Others have begun to forecast how nanotechnology -- the manipulation of matter at the atomic level -- may well allow for eternal repair of human organs and arteries, granting us a kind of physical immortality. All of this work is being pursued aggressively, and with very little in the way of public debate. One reason for writing this book is to try and spark some of that discussion.
But is debate even possible? Won't we inevitably develop these technologies?
The researchers would like us to think so. "Asking whether such changes are 'wise' or 'desirable' misses the essential point," says UCLA's Gregory stock. "They are largely not a matter of choice; they are the unavoidable product of technological advance."
In fact, though, this genie is still in the bottle, if barely. And there is reason to hope we can keep her there. For one thing, we've learned a lot in the last century about controlling technology -- our record with chemical and biological weapons, for instance, while far from perfect nonetheless gives us some hope. And it's worth bearing in mind that one or two enhanced children won't make much difference. For it to become widely commercialized, you'd need an industry with lots of capital, and with some protection from liability and regulation. In other words, you'd need to persuade the public to back it, or at least not to interfere.
A political debate is coming, therefore -- a political debate on what it means to be a human being.
Won't such a debate just pit right wing fundamentalists and pro-life activists against everyone else?
No. These technologies are so new and different that they're already creating a new politics. Last year's congressional debate on cloning was instructive. Some libertarian Republicans backed the right to clone; some pro-choice liberals called for tight restrictions or bans on the technology. Feminist and environmentalist leaders have been outspoken in opposition to these technologies. Speaking about these forms of genetic engineering, Sierra Club president Carl Pope told the convention of the National Abortion Rights Action League, "We must be as vigilant for the whirlpools of extreme instrumentalism as we are for Operation Rescue."
The real division is between those who think every decision can be left to the market, and those who think some decisions must be made by the society as a whole. If there was ever such a choice to be made, this is it.
Your work is mostly as an environmentalist. Do you see these, in part, as environmental issues?
Indeed they are. My best-known book, "The End of Nature," was the first account for a general audience of global warming. It's now in 20 languages and on every continent -- mainly because it described a threshold moment in our history, a change so big that unless we ward it off everything that follows will be different.
The technologies described in "Enough" are the next such threshold change. They take one of the last reserves of the natural -- our individual lives -- and turn them into something very different. The caution of environmentalists, and even more their love of the world that already exists, are necessary to thinking clearly about these choices. Without them we will fall easy prey to the siren song of the human "enhancers," just as we've seen so much of the rest of the natural world disappear in the name of "improvement."
How does this book differ from other books recently published on genetic engineering?
Most of the critical writing about genetic engineering, and these other emerging technologies, concentrates on either the practical problems (it won't work right, babies will be born deformed, etc.) or on the social effects (it will create a breed of elites and thus undermine democracy). Both of these criticisms make sense, and I discuss them briefly -- but I'm more interested in a deeper question: What will it mean to be a human being once we start making such changes? What, ultimately, will it feel like? I think that the greatest dangers are to the very meaning of being human.
Why did you call your book "Enough?"
In the end, these questions run to the very core of what it means to be human. Are we good enough as a species, or are we in need of wholesale improvement? Do we have -- in the West -- enough intelligence, longevity, convenience, comfort, or do we need to remake the world in search of More? I think that the fast advance of technology has taken us to a very important crossroad, and we need to face issues we've always postponed before. If we don't, the technology will take care of them for us.
The author of a recent book on human genetic engineering says it is coming soon, and we must now decide what it means to be human.