It's also important to note that there's a difference between a physical disease like cancer, which is straightforwardly and universally negative, and a complex mental health condition like depression. For one thing, polygenic scores don't perform as well in psychiatry, as psychologist Eric Turkheimer notes. Plus, most mental health conditions come in mild, to moderate, to severe forms, and it's not clear that we should want to get rid of mild or moderate manifestations.
"Sure, it would be nice if no one ever got depressed, but what would that actually mean?" Turkheimer writes. "People are going to be sad, and the most modern models of psychiatric disorders view most of them as extremes on continuous dimensions of normal behavior. I don't think we want some kind of genetic version of Soma."
To give a personal example: I have generalized anxiety with some obsessive tendencies. Is that a major pain in the butt sometimes? You bet. But, if I could wave a magic wand and get rid of it, would I? No. In my experience, this trait is linked to another trait I deeply value: my creativity. The same thing that propels me down rabbit holes of worry also propels me down rabbit holes of getting super curious about some topic, researching it into the wee hours of the morning, and then writing a novel or children's book about it.
That brings me to one other scientific issue: pleiotropy. It's a fancy term for a simple truth, which is that genes can have an effect on more than one trait. When it comes to behavioral polygenic testing, we actually know very little about which genes cause what — a gene that's correlated with depression or anxiety may also be correlated with a bunch of other things. So, if everyone were to start selecting embryos to try to protect their kids from depression or anxiety, what would happen? We don't know!
Pleiotropy is a scientific issue, but it's also a moral issue, because in trying to protect your kid from a negative outcome, you could also be accidentally barring them from a positive one.
And that's just the tip of the moral iceberg.
Another issue is the potential psychological harm that can result from commodifying our kids — treating them like consumer objects with selectable parts. Let's say you use polygenic testing to try to select for high IQ. Even if the company's predictor is right 80 percent of the time, that means it's wrong 20 percent of the time. What happens if it's wrong about your kid, and they end up with a low IQ instead of a high one? How will your kid feel? Unless you hide the truth from them, they'll know that they are not what you wanted, that they failed to live up to the vision you went out of your way to chase.
The same goes for sex selection via good old PGT-A. I know you really want a girl. But, what would happen if you select for a girl, and then your child grows up and turns out to be trans? They may feel an extra sense that they're letting you down by not conforming to the gender expectations you had for them.
Then, there are the ethical questions around unequal access. Polygenic testing isn't cheap. (One company, Orchid, charges $2,500 per screened embryo. Test 10 embryos, and that'll cost you $25,000.) So, at least in the short term, that raises the specter of entrenching a caste system, where the gap between rich and poor expands dramatically as the rich get smarter and stronger.
Technologies tend to get cheaper over time, so maybe everyone will ultimately be able to afford polygenic testing. But that raises another problem: implicit coercion. If more and more of us make ourselves smarter and stronger, we may create a society in which everyone feels pressure to alter their child's biology — even if they don't want to. To refuse embryo selection would mean to put a child at a huge professional disadvantage or to face moral condemnation for making "suboptimal" kids when optimization is possible. Society may no longer offer health insurance benefits or accommodations for kids with disabilities (or even non-enhanced IQ), reasoning that "it was the parents' choice."
Some philosophers, like Julian Savalescu, already argue that parents have a "moral obligation to create children with the best chance of the best life." Polygenic testing companies love that argument; Orchid founder Noor Siddiqui tells parents that "the responsible decision" is to "protect their children" from disease, using language like, "What if you could have stopped it...but chose not to?" And we generally live in a culture that's obsessed with optimization.
So, it's no wonder that you find yourself asking, "If I could do something to make my baby healthier and happier, don't I kind of have to do everything in my power?"
It's a view that will be very appealing to utilitarians, who believe the right action is the action that maximizes well-being or happiness. But maximizing principles can be dangerous. If we're laser-focused on maximizing one value, however noble it may be, that can lead us to overlook a host of other important values. Think about diversity, for example; polygenic testing could lead to a less diverse world.
And it's not even clear how to maximize well-being, given that each embryo will have some downsides. How would you choose between one embryo with a slightly elevated risk for schizophrenia, another with a moderately elevated risk for cancer, and a third with a high risk for Alzheimer's? You'd have to decide how to rank the importance of each condition, which would require a dizzying bit of moral math. How much weight do you put on the longevity associated with each condition, how much on patient-reported quality of life for each condition, and how much on your own ability — and society's ability (which will change over the years) — to cope with each? Plus, even if the screening does end up optimizing life for your individual child, it could have negative effects on the population level for the reasons we covered above.
As Nobel laureate Herbert Simon pointed out, many problems contain way more variables and way too much uncertainty for maximizing along a single axis to be feasible or even desirable. So it often makes sense to just go with an option that's "good enough." He coined the term "satisficing" — a portmanteau of "satisfying" and "sufficing" — to describe opting for this good enough choice.
What would satisficing look like in the context of embryos? If there's a very serious condition that runs in your family — like Tay-Sachs or the BRCA mutation that markedly increases cancer risk — then I do think there's a strong case for screening for that. These conditions are debilitating and can lead to early death. Nobody wants them. Genetic testing that lets us prevent them is an awesome gift.
Then, there are conditions that can include suffering, like autism, but can also be very compatible with a happy life. Mental health conditions, in particular, are heavily socially constructed — a lot of the associated suffering comes about because society constructs a certain biological reality as a problem and doesn't support the people who have it. In these cases, if you want to give your child a "good enough" or even "optimized" life, remember that you don't have to achieve that by biological means; working to change the social environment can be just as important, and it doesn't carry the societal risks associated with polygenic testing.
Ultimately, when considering what counts as a "good enough" life, each parent will draw the line in a slightly different place. And there's a part of that that can't be boiled down to objective facts about disease, because this is also about how well-resourced the parent feels — emotionally, socially, and financially — to deal with a certain condition. What feels manageable to one parent may feel crushingly hard to another.
So, I can't tell you exactly which screenings to do and which to forgo. What I do want to tell you is to resist being bullied or shamed by others, especially those with a profit incentive to push you in a certain direction.
As the epidemiologist Abby Lippman noted, genetic testing is supposed to offer parents more choice, but it too often has the opposite effect. When someone like Orchid's Siddiqui says about a disease, "What if you could have stopped it...but chose not to?" — well, that language preys on parents' worst fears and insecurities. It holds parents hostage while pretending to be giving them more autonomy.
You are nobody's hostage. You are a moral agent free to look at the many different relevant factors, weigh them all in the balance, and then make the choice that works well enough for your family.
