We stand on the precipice of a new epoch of human evolution and the human experience. After eons of
continuity, our evolution is quite suddenly, no longer driven by the familiar edict, ‘survival of the
fittest,’ with its implicit underlying question, ‘who will survive to reproduce?’ Today and for every day
going forward, the question at the heart of our lives is ‘who will be born at all?’
My great grandmother, Elizabeth Glidden Hinman, married at twenty-two, bore at least six children and
buried two, before she died in her forties. Her great granddaughter married at thirty and had two
carefully planned children, with the luxury of confidence that each would in all likelihood live to a ripe
old age. The experience in my own family is mirrored all over the country and the world. The median age of
people in America has doubled in the past 150 years; the average American is twice as old today as in
1880. ...
Women in the United States are marrying later than ever before with a median age of 28 in 2022. The
birthrate in the United States (and in more than half of the countries of the world) has dropped below
replacement value; if the current trends continue, soon we won’t be having enough babies to keep the
world’s population even at its current level. But even as fewer children are born, those that are born
now are much more likely to live to adulthood; the childhood mortality rate in the United States is less
than 1/20th of what it was 100 years ago. These are facts. More importantly, these are the facts that
define our families and our lives.
The family is the elemental unit of human societies, our lived experience, our biology, and our
evolution.
After millennia of broadly similar reproductive pressures, the fabric of our families has changed in the
blink of an evolutionary eye, and likely for good. For time eternal families had lots of children, many
died before they reached adulthood, and almost all died before old age. Those that lived to adulthood,
went on to have families of their own to carry their genes forward. Winnowing at each generation drove
the
evolution of the human species, with the genes that conferred the greatest chance of living to adulthood
being strongly selected for. Today, families across the globe are instead opting to have just a few
children, in part because they are confident that those children they do have will live to adulthood.
The
words ‘opt’ and ‘will live’ are key to this change, which distills down to a simple question. No longer
driven by survival of the fittest, our evolution going forward will be built upon the question of who
will
be born at all.
That deceptively simple reframing has repercussions that ripple out through every aspect of the lives of
all humans: our societies, our economies, our everyday lives, and our biology. A transformation of this
magnitude demands our attention and demands it now, as we cross critical thresholds in fertility, in
survival rates, and even how we reproduce. China’s population peaked in 2022 and is now declining, while
in South Korea the fertility rate fell to 0.72 in 2023. The global fertility rate is currently around
2.3;
we are staring down replacement value worldwide. Meanwhile, child mortality continues to fall both in
wealthy nations and in less wealthy nations. Embryo selection is available for some traits and the first
CRISPR-edited babies have already been born. Reproductive technologies are poised to transform our power
of choice beyond whether to have children to which children we choose to bring into the world.
Two specific developments, each transformative on its own and together truly revolutionary, led to this
moment. First, the advent of “modern” medicine, that is the systematic application of the scientific
method to medicine, created the framework for the ensuing medical discoveries that mean that most
children
born today will live to adulthood. Second, the discovery of effective birth control gave humans the
choice
of whether, when, and how many children to have.
The first evolutionary pathway to consider is the natural process of selection of randomly generated
genetic variants, given the changed pressures set in motion in the Second Epoch. Creating new
evolutionary
pressures, while removing some others, will inevitability redirect the natural process of evolution and
transform the human genome. With possible outcomes including longer lifespan, fewer autoimmune
disorders,
and even the fadeout of violence, it is exciting to consider how this change in evolutionary pressures
will direct the future evolution of humankind.
These are plausible outcomes and thought experiments, extrapolating from the change in natural
evolutionary pressures between the First and Second Epochs of Human Evolution. Because we are at the
very
beginning of this new era, it is impossible to make predictions with certainty, but what is certain is
that we have changed the evolutionary pressures on humans and that that change will have outcomes.
The second mechanism by which modern medicine will cause a shift in the human genome is through active
choice. Either through embryo selection, or by gene editing, we will be intentionally choosing to
reinforce the prevalence of some genes over others in our population. This is a timely moment to
consider
the impact of this technology, which though in its infancy is not purely futuristic. Already today,
parents-to-be that carry the gene for Tay Sachs can choose to use preimplantation genetic testing of
their
embryos to ensure that their future child is not afflicted. This kind of pre-implantation genetic
analysis
increases every year and will expand beyond avoiding lethal genetic profiles to more optional
selections.
And with gene editing technology, parents will be able not only to choose from randomly occurring
embryos,
but also to modify the genes in their embryos to have particular profiles.
Drawing on history, population data, evolutionary biology, and the lived reality of families around the
world, Survival of the Planned reframes the question of evolution for the Second Epoch
of
Human Evolution,
which starts now. It is neither an alarmist panic-read, nor a utopian fantasy, but an informed and
engaging exploration of how modern medicine and reproductive choice are shaping our societies, our
economies, and our genome. The stakes could not be higher. We have, for the first time, the ability to
plan not just our individual futures, but the future of our species. The question is not whether we will
use that power, but how.
You may wonder why I should write this book and part of the answer is that it needs to be written, now,
I
am prepared to take on this challenge. The popular press goes wild for some parts of the narrative, but
both the narrow lens and the five-alarm nature of most reporting do the topic a disservice. From Sir
David
Attenborough, the famous naturalist, threatening that, “We are the only species to have put a halt to
natural selection.” To Elon Musk virtually screaming that, “Low birth rates will end civilization,” we
are
inundated with attention-grabbing headlines portending doom. None of these statements is true. Evolution
has not ended and there is no reason to believe that society is on the brink of collapse. Our
intellectual
landscape urgently lacks an engaging, multi-disciplinary, non-sensationalist exploration of how we got
to
this pivotal moment, when human evolution is no longer predicated on ‘survival of the fittest,’ and what
it means for us all, going forward. This book sets out to do just that.
