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Planet of the (Little) Apes

The Daily Mail has recently published an article entitled ‘Planet of the (little) apes: Save the world by genetically engineering humans to be smaller, suggests NYU philosopher.’ (

 It is always good to see the Daily Mail covering philosophy and covering issues in applied ethics in particular. The NYU philosopher in question is former Uehiro Centre researcher S. Matthew Liao. His co-authors, Anders Sandberg and Rebecca Roache are both affiliated with the Future of Humanity Institute here at Oxford and the paper under discussion is called ‘Human Engineering and Climate Change’ and is forthcoming in Ethics Policy and the Environment, an interdisciplinary academic journal which specialises in environmental policy and ethics.


Liao et al. make the interesting suggestion that we should consider ‘human engineering’ as a possible solution to climate change. Instead of seeking to merely change our behaviour, or seeking to change our environment, we should consider changing who we are, they suggest. They consider various forms of human engineering, the most striking of which (and the inspiration for the headline ‘Planet of the (Little) Apes’) is the suggestion that we should deliberately choose to have smaller children using preimplantation genetic diagnosis, hormone treatment and other possible techniques. A 15% decrease in height will lead to a 15-18% decrease in metabolic rate, according to Liao et al. If the entire next generation was 15cm shorter then that generation would need 15-18% less food than the current one, and surely such a significant drop in the demand for food would lead to a significant decrease in carbon emissions.

 However, Liao et al. are adamant that we ought not to compel people to have smaller children so an entire generation is not going to be 15cm shorter. Instead, like vegans and people who have solar panels on their roofs, Liao et al. contemplate an ethically aware minority who will freely choose to have small children. One reason to think that most people will not voluntarily go along with this plan is that, as the authors acknowledge, the short bear significant disadvantages in our society. It seems that women consistently prefer tall men and taller people tend to enjoy greater career success. Parents who deliberately choose to have smaller children than they would have otherwise are putting the interests of the planet ahead of that of their own children.

 I have a couple thoughts about all of this: The first is that, although the authors consider various possible side effects that such interventions might involve, they fail to consider the psychological consequences for the stunted children of the environmentally conscious parents that they are contemplating. It is possible that these stunted children will go along with their parent’s environmental concerns and appreciate the sacrifice that their parents have decided that they will make for the planet, but it also possible that they will come to resent having these sacrifices forced upon them. An ordinary short teenage boy who fails to attract members of the opposite sex may lament his lack of height but will usually not blame his parents for this state of affairs. But what if he finds out that his parents deliberately decided to make him short for the sake of the planet? That angry little teenager may well come to hate his well-meaning environmentally-aware parents and all manner of unfortunate psychological consequences may result. If he turns out to be the next Napoleon then those unfortunately psychological consequences will impact upon many, many people and perhaps also on the planet.

 My second thought is that it is potentially misleading to call this proposal voluntary. Unless the techniques that are being proposed are somehow made reversible then the children in question will have no choice in the matter. Their parents are deciding for them. As a society we do not give parents an unlimited right to make decisions on behalf of their children. If they are making choices that are clearly harmful to those children, such as refusing to educate them or clothe them properly then we as a society may feel entitled to intervene and prevent those parents from making such poor decisions on behalf of their children. If it turned out that the parents in question were using the money that they had saved by not educating their children, or not clothing them properly on, say, planting trees to help save the environment, then we would be unlikely to consider that to be a sufficient excuse for neglecting their children.

 Now consider the possible case of parents who put their children on a highly restrictive diet with the deliberate aim of preventing them from reaching more than 85% of the height that they would have reached had they had access to what we would ordinarily consider to be a healthy diet; and doing so, so that they will consume less food as adults and be less of a burden on the planet. I suspect that many people would consider such activity on behalf of parents to constitute child abuse and grounds for taking the children away from the parents. This possible case seems to be highly analogous to what Liao et al. are proposing. In both cases parents are deliberately choosing to diminish the future prospects of their children for the sake of the planet. One of them is probably going to be much more painful for the child in question but it is not clear to me that only one of them a form of child abuse.

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8 Comment on this post

  1. If we ever reach that level, why not just use similar technologies to enhance food or engineer bacteria that help reducing/degrading pollution or purifying water?

    Messing with humans will make the whole thing more difficult, as it seems it is already quite hard to debate simple things as abortion and euthanasia.

  2. Matthew mentioned this idea several years ago… I think of all the ideas I’ve heard on the mitigation of climate change it’s one of the most… creative… but like Scott Prudham’s stuff on performativity, green capitalism and climate change**, it strikes me as academic in the DECC-don’t-need-to-worry-about-this-one sense. [Same with personal carbon allowances, the “we can’t solve climate change without the revolution” thing and so forth. Interesting to think about over a pint in the pub, but if they are relevant to climate change it’s on planet Academia, not here on Earth.] Still – I quite like the fact that (some of) these sorts of ideas are bouncing around. Life’s rich tapestry and all that.

    **Available at

  3. Good points that you raise in this post. I haven’t read the paper in question but I wonder whether the authors consider preimplantation genetic diagnosis as a means of producing smaller people. This might mitigate or eliminate your first two concerns, about resentment and psychological effects on the child so produced, and voluntariness, since it introduces non-identity considerations not present in the other techniques discussed. Given this, the weight of the sacrifice made also seems to be shifted from the child to the parents, who would have to forgo less technical means of reproduction and undertake IVF instead. This all assumes that a genetic test for height is developed, but this may be more achievable and safer than genetic engineering to achieve the same result.

  4. Anthony Drinkwater

    Liao et al’s proposition is unfortunately based on the naïve, highly implausible and probably false assumption that smaller humans will have smaller ecological footprints.
    1. It might just be true that smaller people eat less, but it is far from proven. However, it is not quantity that counts in determining the footprint. Eating less in total, but with a higher proportion of meat (they will have more to spend on food therefore could choose to eat more expensively) would arguably be worse.
    2. There is no logic in believing that small people will drive less in more economic cars, use public transport or walk or cycle more, buy fewer iPads, consume less heating or air-conditioning, or differ in any behaviour from their larger counterparts.
    3. To conclude, human behaviour is not mainly driven by biological need (which fact is both its joy and curse).

    1. To add to these concerns, there are some studies that suggest shorter people tend to live longer:

      If this is the case, then the extra years of life could cancel out any other benefits in terms of reduced consumption. Though one could of course argue that gaining extra years of life is an independent reason *for* promoting shortness, if only there were no other (social) costs.

  5. On the first thought. Isn’t there an important difference between e.g. preimplantation diagnosis and hormone treatment? If the child in question was born only because he was going to be short, shouldn’t he (*pace* Randy Newman) count himself lucky to be short?

  6. Thanks all for your comments. As Roger points out there is indeed an important difference between PGD and hormone treatment. In the hormone treatment case an intervention is used to prevent a child from reaching the height that s/he would have reached, all things being equal. In the PGD case, an embryo is selected because it will grow into a short person. The parental choice to use of hormone treatment to stunt growth seems highly likely to lead to resentment by the child as it involves deliberately disadvantaging the child. The use of PGD to select a short child seems to raise a different set of issues, but they are still troubling ones. If the child comes to realise that her parents only decided to have her because she was going to grow up to be a small adult – rather than a different child that would have had better opportunities in life – then issues are raised about the parents relation to the child that may be disturbing to the child. Knowing that the parent passed up the opportunity to have a child who would have had better prospects in life raises the issue about how much the parents actually care about the child. Similar issues are raised in the case of ‘saviour siblings’.

    By the way, I thought about mentioning the great Randy Newman when writing my blog post, but few people in the Uehiro Centre- especially those under the age of 40 – seemed to know who he was.

  7. While the comments presented here are quite rational, people on other sites have criticized of Liao’s paper and are based on a knee-jerk reaction to new ideas. First of all, we have already implemented size control actions through a food system that subjects the population to excess protein, calories, and various chemicals and toxins. We eat animals that have been fed genetically-modified foods, hormones and antibiotics. In contrast, for most of human existence, we ate simple, basic foods and we didn’t have them everyday. Sometimes we went without eating for days. Professors Popkin, Colin Campbell, Cameron, Burkitt and Rollo have noted that our emphasis on meat, processed foods and calories have led to faster aging and increased chronic diseases in middle and older ages. The problem is that we are blinded by our prejudice favoring taller and bigger people. This favoritism is a threat to human survival because 6 to 9 billion bigger humans consume so many more resources along with polluting the environment.

    A world population of bigger people need more metals, minerals, plastics, energy, water, food, and farmland. Yes, taller, larger people eat more food following the same lifestyle.. The needs of taller people are quite large as described in the book: Human Body Size and the Laws of Scaling-Physiological, Performance, Growth, Longevity and Ecological Ramifications, Nova Science, NY, 2007.

Dannenberg calculated that a 10 pound increase in the average American would increase airline fuel consumption by 350 million gallons per year. Jacobson also calculated that a 25 pound increase would require an additional 1 billion gallons of auto fuel per year.

    For readers with an open mind, there’s plenty of research showing that shorter, lighter people have a number of physical advantages (faster reaction times, faster acceleration, stronger pound for pound, and greater endurance). Some of the greatest achievers of all time have been quite small: Mozart, Picasso, Michelangelo, Einstein, Alexander the Great, Alexander Pope, John Keats, Andrew Carnegie, Onassis, David Murdock, Bruce Lee, Jet Li, Jackie Chan, Churchill, President Madison, Maradona, Scott Hamilton, and Tara Lipinski.

    I have studied the ramifications of increasing body size for about 37 years and published over 40 papers and books on the benefits of smaller humans. If the subject interests you, go to website: and Why smaller humans are in our future

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