April 02, 2006
Will Offspring Genetic Engineering Cause Population Explosion?

Several years ago Steve Sailer commented that what parents most want from their children are grandchildren.

Feminists and gay male leaders will also soon grow concerned that allowing parents to select embryos will leave them with fewer followers. This is because free market Galtonism will increase the gap between the sexes. Parents will select for square-jawed, ambitious, high testosterone, first-born sons, and lovely, nurturing, high-oestrogen, latter-born daughters. Why? What parents want most from their children are grandchildren, and high-achieving sons, such as business executives, produce far more grandchildren on average than high-achieving daughters. Further, parents will want loving daughters to take care of them in their old age.

Thus, boys will become more masculine and girls more feminine.

That statement was made in the context of what people will select to give as characteristics to their children and how Lefists will oppose individual choice in offspring genetic because parents will choose characteristics that Leftists, and feminists in particular, will not like.

The focus in that essay on the battle between ideological factions (important though it is) distracted me for years from noticing something far more important: If parents want their children to have grandchildren then won't parents tend to select cognitive characteristics for their children that will cause their children to want to have children of their own? If so, won't that lead to a population explosion?

Lately I happened to have several conversations with friends and acquaintances who were incredibly enthused about becoming grandparents. Then I recalled Steve's comments and got to thinking about the ramifications of so many parents wanting to become grandparents. This strikes me as a big problem once that desire meets up with offspring genetic engineering.

Years ago Mojo Nixon and Skid Roper did a song called "Elvis Is Everywhere" (except in Joan Rivers and Michael J. Fox). Well, Darwin is a lot like Elvis. He's everywhere. Natural selection is happening all around you all the time. Darwinian natural selection is like Spock's brain controlling an entire planet. It is that pervasive.

Currently fertility rates are declining below replacement levels in many Western nations. In the past natural selection ensured reproduction by use of lust. But birth control pills and other methods of contraception have (seemingly) defeated natural selection. But Darwinian natural selection is relentless and not so easily defeated. Therefore I do not buy the argument that the decline in fertility is a one way street.

As I've previously reported on an Australian twins study (see here and here) characteristics that increase fertility appear to be under positive selective pressure in humans. So just from natural selection I expect to eventually see an upswing in fertility in Western populations. But will humans do genetic engineering to their offspring that greatly speeds on selection for the desire for children and hence for increased fertility? This seems plausible, even likely.

Worse yet, suppose some members of future generations are genetically engineered to really really like having children. Then suppose we achieve the ability to rejuvenate using Strategies for Engineered Negligible Senescence (SENS). People will live for thousands of years with youthful bodies. If they have a very strong genetically engineered urge to reproduce they might not be satisfied with just one child. Every one or two hundred years they might plot ways to have more children. If such people become a large fraction of the total population then I could easily envision them achieving a democratic majority to vote for continued unlimited reproductive rights. What happens then? Potentially the birth of tens of billions of humans. The human population could double and double and double again many times.

Anyone see a reason why this won't happen? Getting taken over by AI robots that wipe us out is one way that future might not come to past. But short of that, can a human population explosion be prevented?

Share |      Randall Parker, 2006 April 02 02:15 PM  Trends Demographic

Paul E. said at April 2, 2006 10:57 PM:

I'm not sure that I'd consider it a problem. There's a lot more room on the Earth than we tend to realize. If anything, increased population (and energy appetites) will drive adoption of fission/clean coal technologies, perhaps even orbital colonization. More brains doing more thinking means, effectively, we're rolling more dice that just might come up 'Einstein' or 'Newton'.

rsilvetz said at April 2, 2006 11:13 PM:

Well, as long as they are productive human beings, I don't see a problem. This moves the Malthusian limit right out into the Dyson Ring level.

Hell, if all we did is build an orbital ring and moved the population like in 3001 by Clarke we would be A-OK.

This one, I don't think we should lose sleep over. I would welcome this turn of events. In fact, we should probably actively start pursuing it.

Agnostic said at April 3, 2006 12:41 AM:

You should record an adaptation of Mojo & Skid's "Burn Down the Malls" but rant about illegal immigration.

Scott said at April 3, 2006 8:21 AM:

Not that it matters, but in 'Elvis is Everywhere', Mojo points out that Elvis IS in Joan Rivers...but he is trying to get out...

Tom said at April 3, 2006 9:15 AM:

It may be true that most parents want grandchildren, but it doesn't follow that most people considering becoming parents principally want grandchildren. When I had my daughter, it wasn't really on my mind. That will probably come later. In order for this to follow, new parents need to want grand children, not parents that have already had their kids.

Bob Badour said at April 3, 2006 10:12 AM:


I suspect you were relatively young when you decided to become a father. A person approaching 40 who decides to become a parent is more likely to consider whether they want to become a grandparent at 60 or at 80. That person might just tinker with their child's propensity to have children earlier and more often.

AA2 said at April 3, 2006 1:35 PM:

People already unconciously choose mates who want children. But it could be amplified I am sure, once we understand the brain and the genetics in much greater detail. The thing is human generations still take awhile for the exponential to hit, about 30 years a generation. Thats small in the history of civilization, which is why those pro-reproduction cultures are here today and the cultures which didn't push it as much got bred out.

But in the history of technology 30 years is a long time. I think once we start talking hundreds of years into the future we have got to think about ourselves merging with the machines. Its hard to say whether having children in the biological sense would be something those people would want to do.

No doubt if people started having children out of control we would have to take measures to deal with that. Such as you can have children if you want, but you'll have to go to the mars colony. Right now the issue in the developed nations is lack of children to support our systems!

Mastodon said at April 3, 2006 3:05 PM:

"fly me to the moon, and let's have kids among the stars
let me see the grandkids play on Jupiter and Mars"

space sinatra croons

The Fool said at April 3, 2006 4:10 PM:

_The Mote in God's Eye_ by Jerry Pournell lays out exactly that kind of scenario with alien race the 'moties' who breed even more exponentially than we do. It seems likely that humans will follow the same path.

Honestas said at April 4, 2006 2:23 PM:

Genetically engineering a child is like adopting. Parents will want children similar to themselves.

As for population explosion: war and disease is inevitable.

Antinomy said at April 4, 2006 7:06 PM:

Once we have the ability to tinker with ourselves on such a basic level, why wouldn't we have the ability to reduce population growth if we go too far and the planet starts to become too crowded? If we learn how to increase population, we will simultaneously learn how to decrease it.

At any rate, genetic engineering on that level probably implies the ability to create vast amounts of new wealth that can be used to support a growing population in style.

Bob Badour said at April 5, 2006 7:24 AM:


We are talking about a genetic modification that alters motivation in a child on the basis of a parent's motivation. A person who delays childbearing might alter their child's reproductive motivation to make grandchildren come sooner and more often. We know that the parent considering the intervention is already motivated to have children and their intervention will increase the same motivation in the child.

If one can increase the desire to have children, presumably one can intervene to reduce the desire. If not right away, almost certainly within the next 15 to 20 years before the child becomes the parent.

But what would motivate that later generation to intervene? They are not only motivated by childrearing but are strongly motivated. These people will want lots of children around them and presumably will want a continuing supply of them in the form of grandchildren and great-grandchildren etc. and perhaps even a continuing supply of their own.

Are you proposing that the state will provide the motivation and force the intervention?

Antinomy said at April 5, 2006 3:57 PM:

No, I'm not proposing that the state has to force population control. People have many motivations, some of which conflict with other motivations. We also have the ability to modify our instincts with our intelligence.

Some people are motivated to have children, but most people who like children are also motivated to want a good life for those children and for themselves. If we get a population explosion so bad that it starts harming the quality of life, people--even those who really like kids--are capable of controlling their desire to have lots of them. Furthermore, as we learn more about biology, these types of decisions, in which our intelligence conflicts with our emotions, will be easier to make because we will be able to chemically adjust out emotions to better reflect what our intelligence tells us is right.

Bob Badour said at April 6, 2006 5:27 PM:


The problem I see is these GM people will see themselves as wanting to be good and loving parents, and their intelligence will tell them that is right. In at least some cases, the modification might overrule intelligence.

Plenty of teenaged girls desparately want to become mothers when everything would suggest to the intellect that it is not a good idea.

will said at April 19, 2006 8:03 PM:

the first poster is very misled. first off there is not enough earth. right now with 6.5 billion we are way overboard. Not if everyone lived like the bushman of the kalahari of course, but if everyone lives like we do here in the u.s. or any modernized country we are in serous trouble. In fact if everyone today lived like we do in the u.s. we would need 4 earths to supply our one earth with resources. today in the U.S. we don't have enough land or have enough resources to be self sufficient with our current life style needs. as more and more countries modernize, the more resources will be utilized and the less there will be available and the more irreparable harm will be done. not only that but the way agriculture is going usable land is diminishing do salinization, over harvesting and over grazing. industrial agriculture is unsustainable in the lond run. so frankly we are messing up the earth by taking more out then can be put back in, it takes a century to create 1" of top soil, yet we go through more then that every year. On top of it, it seems to be a world goal to modernize so they can use all the worlds resources

darwin never said survival of the fittest, it is more survival of the fit ins, if we destroy our environment life can't survive, and more people is the wrong way to go.

Its a very dim outlook that not many people relize but we are heading for a brick wall if we continue this course.

Trango Fett said at March 21, 2007 6:04 AM:

Not meaning to distract any of you, but eventualy we will have completely artifical kids. P.S.:sorry bout the spelling, if anything went wrong, but I am only a teenager

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