As usual, this week’s question comes from Gregory Stock’s The Book of Questions: Would you want to choose the sex of your child? What if you could safely pick other qualities: IQ, height, temperament, looks?

Fair warning: If discussions of genetic engineering and the future of human reproduction make you uncomfortable, this might be a good time to scroll through your news feed instead. For everyone else, welcome to a conversation that’s becoming less science fiction and more scientific reality with each passing year.

This week’s question seems deceptively straightforward at first glance. Of course we’d want the best for our children—who wouldn’t? But scratch beneath the surface of that seemingly innocent desire, and you’ll find one of the most ethically complex territories in modern science, where the line between medical necessity and genetic vanity becomes increasingly blurred.

The short answer to this week’s question? I wouldn’t want to choose any of these traits for my hypothetical child. Call me old-fashioned, but there’s something to be said for the phrase “variety is the spice of life.” The idea of my child being a surprise combination of traits passed down by myself and my hypothetical wife appeals to me far more than scrolling through genetic options like I’m customizing a car. Tall, short, brilliant, average, introverted, extroverted—I’m going to love that kid regardless of how those particular dice land.

But here’s the thing: my personal preference aside, this isn’t really a question about individual choice anymore. It’s a question about what we’re collectively comfortable with as a species, because the technology to make these choices isn’t some distant fantasy—it’s knocking on our laboratory doors right now.

The Science of Playing God (Whether We Like That Phrase or Not)

Let’s start with what’s actually possible today, because the gap between science fiction and scientific fact has narrowed considerably in recent years. Scientists can already use preimplantation genetic testing (PGT) to screen embryos for certain genetic diseases during IVF procedures, and sex selection occasionally occurs at this point as well. This isn’t technically genetic modification—it’s more like genetic screening, choosing among existing embryos rather than actively editing their DNA.

But then there’s CRISPR-Cas9, the gene-editing technology that’s changed everything. This technology allows scientists to precisely edit DNA strands, potentially treating and preventing the inheritance of specific genetic diseases. The operative word here is “potentially”—because while the technology exists, experts don’t consider it safe or effective for widespread use.

The poster child for the dangers of rushing this technology is He Jiankui, the Chinese scientist who created the world’s first gene-edited babies in 2018 using CRISPR technology, editing genes to prevent HIV infection. He was imprisoned for three years for violating medical regulations, and his work was widely criticized as reckless and unethical.

Yet here we are in 2025, and the quest to create gene-edited babies is getting a reboot, with Silicon Valley entrepreneurs and venture capitalists eager to push the technology forward. A company called Manhattan Project has announced plans to genetically modify human embryos, with its founder stating they want to “be the company that does this in the light, with transparency and with good intentions.”

The irony of naming your genetic engineering company after the development of nuclear weapons is apparently lost on these folks, but that’s Silicon Valley for you—always confident that this time will be different.

The Hierarchy of Genetic Acceptability

Not all genetic interventions are created equal, and there’s a clear hierarchy of what most people find acceptable. At the top of the acceptability pyramid sits disease prevention. Few people would argue against using genetic technology to prevent a child from inheriting Huntington’s disease or cystic fibrosis. When you’re talking about preventing genuine suffering and early death, the ethical calculus becomes much clearer.

Sex selection occupies a more complicated middle ground. This practice occasionally occurs during the embryo selection phase of IVF, though many countries have regulations against it except for medical reasons. The ethical concerns here aren’t just about individual choice—they’re about societal implications. When entire cultures show strong preferences for one sex over another, individual choices can create profound demographic imbalances with far-reaching social consequences.

Then there’s the enhancement territory—choosing height, intelligence, temperament, and appearance. This is where we leave the realm of medical necessity and enter the world of genetic consumerism. Some pronatalists argue that parents should have the right to “give their children every privilege they can,” including genetic advantages. But this is where many ethicists start reaching for the emergency brake.

The fundamental question becomes: where do we draw the line between treating genetic conditions and designing genetic advantages? And who gets to decide where that line falls?

The Democracy Problem of Designer Babies

Perhaps the most troubling aspect of genetic selection technology isn’t the technology itself, but who will have access to it. The combined expense of testing and IVF means that unequal access to these technologies will continue to be an issue. We’re potentially creating a world where genetic advantages become just another luxury good, available to those who can afford them while everyone else makes do with natural genetic lottery.

Imagine a future where the children of the wealthy don’t just inherit financial advantages, but actual genetic ones—enhanced intelligence, disease resistance, improved physical capabilities. We could be looking at the biological stratification of society, where class differences become literally encoded in our DNA.

This isn’t just speculation. Companies like Orchid Biosciences are already marketing genetic testing services to help couples select embryos, with their “Couple Report” costing $1,100 and embryo selection services launching soon. The fact that these services are being developed in Silicon Valley, marketed with the same language used to sell any other premium product, should give us pause.

The Slippery Slope Isn’t a Fallacy When It’s Greased

Critics of genetic enhancement often invoke the slippery slope argument—that starting with medical treatments will inevitably lead to cosmetic modifications and eventually to a new form of eugenics. Proponents dismiss this as fear-mongering, arguing that we can draw clear ethical lines between therapy and enhancement.

But here’s the problem: those lines aren’t nearly as clear as we’d like them to be. Is selecting for height to prevent dwarfism therapy or enhancement? What about choosing genes that reduce the risk of depression or increase cognitive ability? When does prevention become optimization?

The potential for unintended consequences is enormous, as off-target genetic editing could lead to cancer or other diseases, and the effects might not appear until later in life. We’re not just experimenting on individual children—we’re potentially altering the human gene pool for future generations.

The aforementioned scientist He Jiankui thought he was preventing HIV infection, but the gene he targeted, CCR5, may have functions we don’t fully understand, and disabling it could have unexpected consequences. Science is littered with examples of interventions that seemed beneficial until we discovered their unintended effects decades later.

The Paradox of Parental Love

There’s a deeper philosophical question lurking beneath all the technical and ethical considerations: what does it mean to love a child unconditionally if you’ve conditioned their very existence on meeting certain genetic specifications?

The desire to give our children every advantage is natural and admirable. But there’s something fundamentally different between choosing a good school district and choosing your child’s DNA. When we start designing our children’s genetic makeup, are we loving them for who they are, or are we loving the idea of who we think they should be?

I keep coming back to that phrase about variety being the spice of life. Some of humanity’s greatest contributions have come from people who might not have made it through a genetic screening process. Would we have had Stephen Hawking if his parents could have screened out ALS? Would we have had Temple Grandin if autism could be eliminated before birth?

This isn’t to romanticize genetic conditions—real suffering is involved, and no one should be forced to endure debilitating disease for the sake of preserving human diversity. But it’s worth acknowledging that our definitions of “optimal” genetics might be more limited than we realize.

The Regulation Challenge

Currently, U.S. federal law prohibits using federal funds for germline gene therapy research and bans implanting genetically modified embryos into a uterus. But observers note that regulations could change under a Trump administration with its deregulatory stance and support for reproductive technologies.

The global nature of this technology creates additional complications. Even if one country maintains strict regulations, others might take a more permissive approach, creating genetic tourism markets where the wealthy can access services unavailable in their home countries.

We’re essentially in a race between technological capability and regulatory wisdom, and right now, technology appears to be winning. The convergence of venture capital, pronatalist ideology, and advancing gene-editing technology is creating momentum that may be difficult to control.

Living with Genetic Uncertainty

Perhaps the most honest answer to this week’s question is that we’re not really ready for it. The technology exists, but our understanding of its implications—both intended and unintended—is still catching up. Researchers emphasize that these germline genetic editing methods should still be considered experimental procedures, with continued research needed to improve safety and assess long-term effects.

In the meantime, we’re left with individual choices that have collective consequences. Every couple that chooses genetic screening or selection isn’t just making a decision for their own family—they’re participating in a broader social experiment about what kinds of humans we want to create.

My personal inclination toward genetic acceptance rather than genetic engineering might be naive in a world where other parents are optimizing their children’s DNA. But I’d rather err on the side of embracing human unpredictability than risk creating a world where genetic diversity becomes a luxury good.

The question isn’t really whether we should want to design our children—it’s whether we’re wise enough to handle the consequences of that power. Based on our track record with other powerful technologies, I’m not particularly optimistic about our collective wisdom.

But perhaps that’s exactly why we need to have these conversations now, while we still have the luxury of choosing restraint over capability. Because once we fully embrace the role of genetic architects, there might be no going back to the beautifully chaotic lottery that has defined human reproduction for millennia.

The Bottom Line

Would I want to choose my child’s sex, IQ, height, temperament, or looks? No. I’d rather be surprised by the unique combination of traits that emerges from the genetic contribution of two people who decided to create a life together. I’d rather love my child for who they are than for who I designed them to be.

But more importantly, I’d rather live in a world where children are valued for their inherent worth as human beings, not for how well they conform to their parents’ genetic specifications or society’s definition of optimization.

Call me old-fashioned, but some things are worth leaving to chance—especially when that chance has been working pretty well for our species for the past few hundred thousand years.

What about you? Would you want to design your child if you could? Where would you draw the line between medical necessity and genetic enhancement? And what kind of world do you think we’re creating when we treat human genetics like a customizable product? Share your thoughts in the comments—this is one conversation where we all have a stake in the outcome.