>But here, too, the right approach is to be cautiously liberal: the burden is on society to justify when and why it is wrong to edit the genome.
I think this sentiment hits the right note. I am wholly unpersuaded by moral arguments about "playing God". We've been doing that for our entire existence. Quite successfully, thank you very much.
But tinkering with our genome and that of our children does present ethical quandaries that need to be discussed and resolved. By allowing by default except where there is a compelling objection, we can both avoid the majority of the negative consequences while embracing the real positives that gene modification will bring.
And the countless people whose lives were saved by medical research might disagree with yours.
"Playing God" simply means changing the universe to better suit our needs. It is a synonym for "maximizing human agency", and it's a damned good thing.
You must admit though that humans will sometimes do misguided things with good intentions? There are many examples of us thinking that we fully understand a process, when in reality we don't. This can and has led to terrible consequences in the past. One concern I harbor is that perhaps with gene modification we will lose the genetic variability that allows animals to adapt and survive and evolve further. Variability also allows species to survive black swan events.
Sure, it's an ethical quandry to play with an unborn child's genes, but keep in mind, these children will be born to the same parents who elect to modify them. A parent who wants to genetically modify their child is a parent who has plenty of resources to raise a child, and plenty of good-will toward their child to the point where they are trying to intervene even before the child is born. These children who are genetically modified would likely grow up being sent to piano lessons, math tutors, and little league.
So what if they're genetically modified to be good at these things? That's a child who will grow up with a leg up on the world already. This is the next step of our species evolution.
The ethical problem isn't necessarily with the individual or even the family.
Genetic engineering isn't so simple. Genes frequently have multiple functions. You might edit a few genes and give someone a high IQ, but those same set of genes now make them socially inept.
So let's say tons of parents do this. You now have a generation that can't effectively socialize and communicate. How does that affect our species as a whole?
Most of humanity's accomplishments are a direct result of our ability to work together. We may worship the individual, but it's groups of people that actually get things done. So by tweaking that one little tidbit to increase IQ, you completely threw the delicate balance out of whack and sent everybody back to the stone age.
That's just one hypothetical example.
By bringing gene selection purely to the parent level, you're excluding millions of years of evolutionary pressure for the sake of whatever happens to be fashionable in that moment.
The good news is that most genetic modifications will have immediate and nasty consequences. You can dick around with corn and have fields upon fields that go bad and simply pick out the winners ... try doing that with human beings and there will be a huge outcry, very quickly.
How about they start by testing parents for matching recessives that cause genetic disorders so they can know to have an Amniocentesis to make a decision on the child's viability?
Being able to edit out the bits for hemophilia, Downs Syndrome, Parkinson's, or <the genetic disorder you're familiar with here>?
It isn't all about trying to create some designer super race. Some parents knowing that they both carry dangerous recessive genes decide it isn't worth the risk of creating a child only to watch it suffer. More testing is good and IMHO ought to be strongly advised.
Personally, I think aborting an embryo that will be born to live with serious defects or illnesses is the first answer, at least until embryonic genetic editing is viable in all cases.
> Being able to edit out the bits for hemophilia, Downs Syndrome, Parkinson's, or <the genetic disorder you're familiar with here>?
Don't misunderstand, I'm totally for this. In the cases you mention we have a proper baseline. We know exactly what will happen when we do the edits, on average. We are returning to the norm, not deviating from it.
The issue is all this super race talk that crops up around these discussions. It's just stupid.
I agree, but the super human stuff is anathema to the majority. I think it is only because of the conditioning they've had from reading novels (or from someone else's opinion after they read such a novel) where editing resulted in disaster and war.
It'll take time to defeat the bad publicity from fiction.
Evolutionary pressure has adapted us to an outdoor agrarian life. Few of us live that life. Its entirely possible to deliberately design people who fit into modern cities. Evolution just got a jet engine.
> Evolutionary pressure has adapted us to an outdoor agrarian life.
If that was the case, you would still be poking some rock with a stick covered in mud growing some wheat instead of typing on a keyboard, talking to somebody over the internet.
Evolutionary pressure adapted you to have a malleable brain capable of whatever is needed at the moment.
> Its entirely possible to deliberately design people who fit into modern cities.
Sure it is. Because we already fit into modern cities just fine. They're designed to our nature, by definition, since we designed them.
Shrug, if we have a new generation that can't socialize but is super smart then that's the next wave of humanity and it's our job to get support them and make sure they succeed. The alternative is trying to beat the genetics out of them, which won't work.
You might feel less positively disposed towards a new generation that's super smart but sociopathic, especially if they have a superiority complex over the genetically normal...
In practice, I'd be more worried about well-intentioned mass modifications having more mundane negative consequence, like creating generations whose unusual metabolism means they're very unlikely to become overweight but highly likely to die very painfully in their early forties.
Its only the 'mass' part of that which is different from the status quo. Already maladaptive genes are laced throughout our population. Tinkering has the risk of producing large numbers of identical modifications. Its debatable whether that means more, or fewer, or the same number of folks will suffer compared to how its done now (random chance).
> Its only the 'mass' part of that which is different from the status quo.
That's pretty important though. The status quo is that maladaptive traits tend to spread very slowly, if at all, in populations. Random chance might give somebody a mutation which gives them an unusually fast metabolism and disproportionate chance of an painful early death, but its not going to spread the mutation across a generation in the way that a marketing campaign for SlimKids(TM) could.
Whether more folks will suffer than before in the long term is less a matter of debate and more a case of how restrictive the use cases are.
For context, we live in a world where despite serious worries about antimicrobial-resistant pathogens, the most common uses of antibiotics are as chicken feed and placebos for the common cold.
Even if popular human genetic modifications are entirely benign there's reason to be concerned about the effect on genetic diversity if certain combinations become near-universal in a population.
The reality is that most progress sits on the recklessness (or even callousness) of those willing to achieve it, and then carries over in the ensuing generations and we take all progress for granted as as inherently good. Probably the Chinese or somesuch government will start messing with generations (and not even in secret) and any outcry won't be much effective. Then, later, science will absorb the consolidated knowledge.
> ... and plenty of good-will toward their child to the point where they are trying to intervene even before the child is born.
Sure they do - right up until it goes wrong. How many of those parents are prepared to unconditionally love their children if they are born crippled, say? It seems to me that the parents who want their children to be "better" are less likely to love them as they need if they come out "wrong".
I agree with you that editing the human genome is not generally ethically objectionable and should be allowed, but I also think that tinkering with our genome will create a whole new set of societal issues that will reinforce the current ones, which humanity has been historically bad at solving.
Imagine a world where genetical engineering is very effective, but not cheap. The already advantaged can create designer babies and therefore have the ability to give their offspring an additional edge. Social mobility could be seriously limited if unmodified humans have a worse chance to get good work or work at all. Even today, many people see the poor as inferior because they often have a bad education. In the future, they could be legitimately genetically inferior.
Gattaca (1997) is an excellent movie with a similar theme: “A genetically inferior man assumes the identity of a superior one in order to pursue his lifelong dream of space travel“.
I'm always pretty skeptical of the worry that this will be restricted to wealthy. For one, I don't think it would (or at least not for long), but additionally, won't that just mean that the people with these benefits will just out compete the rest? So over time everyone alive will have whatever the benefits are even if slowly. This is just a much faster version of natural selection.
In other words, in the long run it won't matter is all I'm saying.
I was talking about this with a friend a few weeks ago, and my conclusion is that this is going to be like giving a bunch of 12 year olds shotguns: beautiful and messy.
We can talk about 'rules' all we want here in the west but there is no way you are going to be able to regulate this stuff and trying to ban the ingredients is just going to lead to people buying it from less reputable sources that have impurities so you will end up with spliced up babies that have a bunch of additional defects instead of just spliced up babies.
We can try to explain to our fellow citizens that there is in fact no such thing as an intelligence gene, but that won't stop them from wanting it and certainly won't stop the snake oil salesmen from selling it. We've never been here before and we learn by trial and error, just like evolution.
There are genes associated with intelligence, they are what makes humans so much more dangerous than any other creature on earth, and octopi so much more interesting than fish.
More to your point, there are some intelligence genes that some people have and other people don't. They don't solely determine IQ, it's a complex interaction of environment, diet, education, personality, etc., but that's not to say they don't exist.
So what if someone's more intelligent? There was an experiment showing that super smart people don't have much of an advantage over smart people. Past a certain point it doesn't matter.
Most other human attributes that we perceive as desirable like height have their downsides (every extra centimeter takes 3 months away from your life plus many other health problems).
I see the opportunity more along the lines of removing health problems such as schizophrenia, etc.
I'm a molecular biologist and know a couple of things about CRISPR. I'm also a philosopher, and know a couple of things about ethics. In college, I minored in bioethics.
"Germ line" editing and production of designer babies as well as genetic re-tooling of already living people is going to happen with 100% probability. Right now there's already embryonic screening for certain (mostly pathogenic) traits, but this will be supplanted by writing and editing of desired traits.
There are not going to be any long term barriers whatsoever; the future of mankind is one of directed synthetic genetics. There will be roadblocks from the regressive factions, of course, but they'll ultimately fail. The millenials will be the ones to start to integrate this technology from the laboratory into normal human existence. Many members of generations that come after millenials will likely be heavily genetically modified, which brings us to an interesting place: the people who are currently being born right now are some of the last humans with fully "organic" genomes. This also means that our future as a species is radically more uncharted at this juncture than it has been since start of the industrial revolution.
Opening the door to synthetic genetics is going to also create new gulfs between the peoples of the world, as the norms that different societies have regarding genome editing will be different. Think Indians behave weird relative to Westerners? Well, you haven't even met the Indian whose parents decided that his genome would be engineered to be the most effective medical doctor. Not only is this guy foreign, he's literally made for a different purpose than you or I. It's extremely likely that his biological intelligence and focus will surpass unaugmented people, and that will breed jealousy and hatred. Among certain populations of people, genetic augmentation will be taboo, so there will be a new undercurrent of "maybe he's augmented" when a newcomer seems to perform strongly. Weird to think about these small details, but they're coming. As I briefly mentioned before, it'll be possible to engineer people for a certain purpose. Even right now, the knowledge of the genetics of intelligence is advanced enough to give this a very good shot. There's always room for unintended consequuences, but we'll wait and see.
As usual, the technology itself is neither good nor evil, but the usages of it will serve both ends and likely remake future human generations moving forward. The next thing that comes to mind is price: affording gene screening and editing is out of bounds for most people right now, so it'll only be the rich, for a time. Eventually the technology will be cheap and ubiquitous, with most middle class people deciding whether or not to genetically modify themselves and their prospective children broken mostly along ethnic religious/political lines. My immediate expectation is that the major powers (US, Russia, China, and EU) will allow for wild "abuses" such as allowing or subsidizing the intentional genetic extinction of certain undesirable traits or malignancies. Some of the worst abuses will probably occur when a government edits the genomes of certain minorities to prevent them from reproducing. It's extremely unlikely that any race of people or any negative trait will go completely extinct, though.
Exciting time ahead, to be sure. I really hope that there are people working on viral vectors to use with this technology so that currently living people can have their genomes edited too.
> the worst abuses will probably occur when a government edits the genomes of certain minorities to prevent them from reproducing
Do you have a specific scenario in mind here? I can't imagine any government getting away with this any more than they could get away with a conventional mass sterilization program.
What if your parents chose a genome for a career that became obsolete? You could have been engineered to be the world's best buggy-whip maker, but if no one wants buggy-whips anymore (and they know you were targeted for that particular skill set from before birth), would you be employable in a different field?
Because buggy-whip making is in your genes, and that'd be tough to overcome.
That's not a problem we're likely to face though. Beyond encoding a physical dependance on some facet or condition of a job, there's very little we can conceivably do genetically to lock someone into just one job. Learnable skills rather than raw genetic aptitude are the requirements for most jobs anyways.
Nature already chose your genome to excel at hunting animals in groups and gathering berries off of the ground. I'm guessing your full time occupation involves neither of those things, even under very broad definitions. We're extremely adaptable.
I feel enraged that option NOT to enhance humanity is even in the picture.
I guess that's the inevitable part of any new medical advance, be it vaccines, anaesthesia or even washing hands when dealing the pregnant women after working with corpses.
Please consider that a decision NOT to change genetic material of "germ line" cells may be because humanity decides it would actually cause a decline of humanity, not an enhancement.
Real social, economic and political factors are going to come into play here. As the author concludes: "Gene editing raises the spectre of parents making choices that are not obviously in the best interests of their children. Deaf parents may prefer their offspring to be deaf too, say; pushy parents might want to boost their children’s intelligence at all costs, even if doing so affects their personalities in other ways. And if it becomes possible to tweak genes to make children smarter, should that option really be limited to the rich?"
I think one of the more realistic fears of this technology is that there won't really be a choice. The option "remain unmodified and live an OK life" simply won't exist.
If that is the case, that it's so successful you pretty much have to do it, that sounds like an absolute success. Sounds like the process pretty much works and is good.
Why do you suppose that children with edited genetics would be a result of parents wanting the best for them?
I think it vastly more likely that (lets call them East German) government agents would be impersonally having children edited, so that their country would win more medals at the olympics. These supposed government agents wouldn't care that these adults would burn out and die of terrible diseases in their mid-lives. They wouldn't care that there might only be a 5% success rate, and that the other 95% had terrible lives.
Thats why the option to NOT edit the human race is on the menu, but I am confident that that option won't be taken, except officially by the nations which are bothered by ethics. We as a race will tinker.
Parents get to bias their children from the moment they are born, and for decades after. This is unavoidable. Doing it with genes is probably no more invasive, and probably a whole lot more scientific.
One issue is gene diversity. Even if most parents are making ethical decisions, at some point there will be standard, best choices. But a species with a gene pool that is not diverse is more vulnerable.
Deaf parents may prefer their offspring to be deaf too, say; pushy parents might want to boost their children’s intelligence at all costs, even if doing so affects their personalities in other ways.
I have read enough to know that certain serious genetic disorders tend to correlate to high IQ. So, yeah, this is very much a two-edged sword situation. It may not be possible to just select for all "positive" qualities.
My concern is not exactly ethics per se. My concern is that genes are complicated and my suspicion is we aren't as clever as we think we are and this could lead to bigger problems than the ones we hope to resolve via this path.
Well this brings up an interesting question: if a given gene/gene expression correlates with multiple effects, some good and some bad, would it be possible with sufficient knowledge to engineer the desired effect from scratch in a way that avoids the undesired effect?
I assume that no one currently has the knowledge of how to do this and won't for decades at least... But interesting to consider!
Interesting to consider, but we're not reprogramming human DNA so much as adding and removing bytes to the compiled output by trial and error.
In practice, there's good reason to be concerned that we might achieve the opposite: popularise a modification with a reasonably well understood "positive" characteristic and then discover the negative effects on many thousands of humans that have had the modification some time afterwards. Of course this happens with conventional medicine too, but it's a little easier to trial a remedy when you don't have to create new humans for each trial, and negative effects are less likely to be irreversible when they're caused by something sufferers take rather than something sufferers are.
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[ 3.3 ms ] story [ 139 ms ] threadI think this sentiment hits the right note. I am wholly unpersuaded by moral arguments about "playing God". We've been doing that for our entire existence. Quite successfully, thank you very much.
But tinkering with our genome and that of our children does present ethical quandaries that need to be discussed and resolved. By allowing by default except where there is a compelling objection, we can both avoid the majority of the negative consequences while embracing the real positives that gene modification will bring.
The many victims of the various eugenics movements of the 19th and 20th centuries might disagree with this sentiment.
"Playing God" simply means changing the universe to better suit our needs. It is a synonym for "maximizing human agency", and it's a damned good thing.
So what if they're genetically modified to be good at these things? That's a child who will grow up with a leg up on the world already. This is the next step of our species evolution.
The ethical problem isn't necessarily with the individual or even the family.
Genetic engineering isn't so simple. Genes frequently have multiple functions. You might edit a few genes and give someone a high IQ, but those same set of genes now make them socially inept.
So let's say tons of parents do this. You now have a generation that can't effectively socialize and communicate. How does that affect our species as a whole?
Most of humanity's accomplishments are a direct result of our ability to work together. We may worship the individual, but it's groups of people that actually get things done. So by tweaking that one little tidbit to increase IQ, you completely threw the delicate balance out of whack and sent everybody back to the stone age.
That's just one hypothetical example.
By bringing gene selection purely to the parent level, you're excluding millions of years of evolutionary pressure for the sake of whatever happens to be fashionable in that moment.
The good news is that most genetic modifications will have immediate and nasty consequences. You can dick around with corn and have fields upon fields that go bad and simply pick out the winners ... try doing that with human beings and there will be a huge outcry, very quickly.
Not just one generation -- Crispr changes are passed down inter-generationally.
How about they start by testing parents for matching recessives that cause genetic disorders so they can know to have an Amniocentesis to make a decision on the child's viability?
Being able to edit out the bits for hemophilia, Downs Syndrome, Parkinson's, or <the genetic disorder you're familiar with here>?
It isn't all about trying to create some designer super race. Some parents knowing that they both carry dangerous recessive genes decide it isn't worth the risk of creating a child only to watch it suffer. More testing is good and IMHO ought to be strongly advised.
I had thought to mention it, but didn't want the thread to deviate to a morals discussion ;-)
The whole discussion invites similar moralizing though, at least until the techniques are known to be very precise and safe.
Don't misunderstand, I'm totally for this. In the cases you mention we have a proper baseline. We know exactly what will happen when we do the edits, on average. We are returning to the norm, not deviating from it.
The issue is all this super race talk that crops up around these discussions. It's just stupid.
It'll take time to defeat the bad publicity from fiction.
If that was the case, you would still be poking some rock with a stick covered in mud growing some wheat instead of typing on a keyboard, talking to somebody over the internet.
Evolutionary pressure adapted you to have a malleable brain capable of whatever is needed at the moment.
> Its entirely possible to deliberately design people who fit into modern cities.
Sure it is. Because we already fit into modern cities just fine. They're designed to our nature, by definition, since we designed them.
> Evolution just got a jet engine.
Fueled by synergy?
Our brain is good at adapting, sure, but not endlessly. Depression, drug use, crime all point to maladaptation.
In practice, I'd be more worried about well-intentioned mass modifications having more mundane negative consequence, like creating generations whose unusual metabolism means they're very unlikely to become overweight but highly likely to die very painfully in their early forties.
That's pretty important though. The status quo is that maladaptive traits tend to spread very slowly, if at all, in populations. Random chance might give somebody a mutation which gives them an unusually fast metabolism and disproportionate chance of an painful early death, but its not going to spread the mutation across a generation in the way that a marketing campaign for SlimKids(TM) could.
Whether more folks will suffer than before in the long term is less a matter of debate and more a case of how restrictive the use cases are.
For context, we live in a world where despite serious worries about antimicrobial-resistant pathogens, the most common uses of antibiotics are as chicken feed and placebos for the common cold.
Even if popular human genetic modifications are entirely benign there's reason to be concerned about the effect on genetic diversity if certain combinations become near-universal in a population.
Sure they do - right up until it goes wrong. How many of those parents are prepared to unconditionally love their children if they are born crippled, say? It seems to me that the parents who want their children to be "better" are less likely to love them as they need if they come out "wrong".
Imagine a world where genetical engineering is very effective, but not cheap. The already advantaged can create designer babies and therefore have the ability to give their offspring an additional edge. Social mobility could be seriously limited if unmodified humans have a worse chance to get good work or work at all. Even today, many people see the poor as inferior because they often have a bad education. In the future, they could be legitimately genetically inferior.
Gattaca (1997) is an excellent movie with a similar theme: “A genetically inferior man assumes the identity of a superior one in order to pursue his lifelong dream of space travel“.
In other words, in the long run it won't matter is all I'm saying.
We can talk about 'rules' all we want here in the west but there is no way you are going to be able to regulate this stuff and trying to ban the ingredients is just going to lead to people buying it from less reputable sources that have impurities so you will end up with spliced up babies that have a bunch of additional defects instead of just spliced up babies.
We can try to explain to our fellow citizens that there is in fact no such thing as an intelligence gene, but that won't stop them from wanting it and certainly won't stop the snake oil salesmen from selling it. We've never been here before and we learn by trial and error, just like evolution.
More to your point, there are some intelligence genes that some people have and other people don't. They don't solely determine IQ, it's a complex interaction of environment, diet, education, personality, etc., but that's not to say they don't exist.
Most other human attributes that we perceive as desirable like height have their downsides (every extra centimeter takes 3 months away from your life plus many other health problems).
I see the opportunity more along the lines of removing health problems such as schizophrenia, etc.
"Germ line" editing and production of designer babies as well as genetic re-tooling of already living people is going to happen with 100% probability. Right now there's already embryonic screening for certain (mostly pathogenic) traits, but this will be supplanted by writing and editing of desired traits.
There are not going to be any long term barriers whatsoever; the future of mankind is one of directed synthetic genetics. There will be roadblocks from the regressive factions, of course, but they'll ultimately fail. The millenials will be the ones to start to integrate this technology from the laboratory into normal human existence. Many members of generations that come after millenials will likely be heavily genetically modified, which brings us to an interesting place: the people who are currently being born right now are some of the last humans with fully "organic" genomes. This also means that our future as a species is radically more uncharted at this juncture than it has been since start of the industrial revolution.
Opening the door to synthetic genetics is going to also create new gulfs between the peoples of the world, as the norms that different societies have regarding genome editing will be different. Think Indians behave weird relative to Westerners? Well, you haven't even met the Indian whose parents decided that his genome would be engineered to be the most effective medical doctor. Not only is this guy foreign, he's literally made for a different purpose than you or I. It's extremely likely that his biological intelligence and focus will surpass unaugmented people, and that will breed jealousy and hatred. Among certain populations of people, genetic augmentation will be taboo, so there will be a new undercurrent of "maybe he's augmented" when a newcomer seems to perform strongly. Weird to think about these small details, but they're coming. As I briefly mentioned before, it'll be possible to engineer people for a certain purpose. Even right now, the knowledge of the genetics of intelligence is advanced enough to give this a very good shot. There's always room for unintended consequuences, but we'll wait and see.
As usual, the technology itself is neither good nor evil, but the usages of it will serve both ends and likely remake future human generations moving forward. The next thing that comes to mind is price: affording gene screening and editing is out of bounds for most people right now, so it'll only be the rich, for a time. Eventually the technology will be cheap and ubiquitous, with most middle class people deciding whether or not to genetically modify themselves and their prospective children broken mostly along ethnic religious/political lines. My immediate expectation is that the major powers (US, Russia, China, and EU) will allow for wild "abuses" such as allowing or subsidizing the intentional genetic extinction of certain undesirable traits or malignancies. Some of the worst abuses will probably occur when a government edits the genomes of certain minorities to prevent them from reproducing. It's extremely unlikely that any race of people or any negative trait will go completely extinct, though.
Exciting time ahead, to be sure. I really hope that there are people working on viral vectors to use with this technology so that currently living people can have their genomes edited too.
-- blindcavefsh on Reddit
you want to raise taxes and you're rich? you're just a hypocrite"
-- stupid people everywhere
Can't wait til the same argument is busted in favor of literal cartoonishly evil Master-race manufacturing.
Do you have a specific scenario in mind here? I can't imagine any government getting away with this any more than they could get away with a conventional mass sterilization program.
> I really hope that there are people working on viral vectors to use with this technology...
Because buggy-whip making is in your genes, and that'd be tough to overcome.
I guess that's the inevitable part of any new medical advance, be it vaccines, anaesthesia or even washing hands when dealing the pregnant women after working with corpses.
Real social, economic and political factors are going to come into play here. As the author concludes: "Gene editing raises the spectre of parents making choices that are not obviously in the best interests of their children. Deaf parents may prefer their offspring to be deaf too, say; pushy parents might want to boost their children’s intelligence at all costs, even if doing so affects their personalities in other ways. And if it becomes possible to tweak genes to make children smarter, should that option really be limited to the rich?"
Maybe very intelligent deaf humans would outcompete the rest of mankind in a few generations? You may not like that, but why exactly should I care?
Parents do have the best interest of their children in mind. Let them be free of making the best choices instead of government imposed ones.
Moloch[1] may demand sacrifice.
[1] http://slatestarcodex.com/2014/07/30/meditations-on-moloch/
I think it vastly more likely that (lets call them East German) government agents would be impersonally having children edited, so that their country would win more medals at the olympics. These supposed government agents wouldn't care that these adults would burn out and die of terrible diseases in their mid-lives. They wouldn't care that there might only be a 5% success rate, and that the other 95% had terrible lives.
Thats why the option to NOT edit the human race is on the menu, but I am confident that that option won't be taken, except officially by the nations which are bothered by ethics. We as a race will tinker.
I have read enough to know that certain serious genetic disorders tend to correlate to high IQ. So, yeah, this is very much a two-edged sword situation. It may not be possible to just select for all "positive" qualities.
My concern is not exactly ethics per se. My concern is that genes are complicated and my suspicion is we aren't as clever as we think we are and this could lead to bigger problems than the ones we hope to resolve via this path.
I assume that no one currently has the knowledge of how to do this and won't for decades at least... But interesting to consider!
In practice, there's good reason to be concerned that we might achieve the opposite: popularise a modification with a reasonably well understood "positive" characteristic and then discover the negative effects on many thousands of humans that have had the modification some time afterwards. Of course this happens with conventional medicine too, but it's a little easier to trial a remedy when you don't have to create new humans for each trial, and negative effects are less likely to be irreversible when they're caused by something sufferers take rather than something sufferers are.