Biblical Boundaries for Human Gene Editing

Genetically modified humans no longer exist only in science fiction. Recent technological advances have ushered human gene editing (HGE) from the realm of Brave New World to the horizon of scientific possibilities. These possibilities became realities in 2018, when biophysicist He Jiankui infamously announced the birth of twins whose DNA he had modified using the gene editing tool known as CRISPR.1

A breakthrough so significant it won the Nobel Prize in chemistry, CRISPR allows for quickly, precisely altering DNA.2 Such tools, like most technologies, can be applied for helpful or harmful purposes and may lead to unintended consequences. For instance, although HGE technologies unlock novel possibilities for curing diseases, concerns about HGE’s safety, appropriateness, and social dangers have led to high-profile reports calling for a global ban on certain HGE practices—at least for now.3

As HGE becomes increasingly available, accepted, and popular, Christians must know how to draw biblical boundaries in response. The following discussion examines relevant theological, scientific, and ethical factors to help believers think biblically about where those boundaries lie.

Gene Editing and Human Origins

Because our beliefs about human origins shape our conclusions about HGE ethics, thinking biblically about HGE requires considering how God’s Word, in contrast to a naturalistic worldview, portrays humanity. This portrayal begins in Genesis, which depicts humans as finite, embodied, morally accountable creatures fashioned in God’s image for relationship with him and with one another. Genesis further reveals that after creating humans, God called everything he had made very good (Genesis 1:31).

So, fulfilling our call to love others (Matthew 22:34–40) now includes responsibilities to mitigate the curse’s effects, where possible, within biblical moral boundaries.

Scripture’s origins account aligns with a “mimetic view” of reality, which sees the world as having meaningful givenness and orderliness setting boundaries on what creatures can (or should) do.4 For instance, a biblical view of family mimetically regards children as gifts to be received from the Creator rather than as products to manufacture—a contrast which some authors infer from the terms pro-creation versus re-production.5 This example highlights how contentment, gratitude, and worship mark the proper human response to life in a given, good creation. Importantly, though, Genesis also reveals that human rebellion brought death, suffering, and other effects of sin’s curse into creation.6 So, fulfilling our call to love others (Matthew 22:34–40) now includes responsibilities to mitigate the curse’s effects, where possible, within biblical moral boundaries.

In contrast, naturalism sees humans as evolved animals with only instinctive or socially constructed morality.7 Humans possess no transcendent meaning but are naturally programmed to perpetuate their purposelessness through survival and reproduction. This evolutionary perspective engenders a “poietic view,” which, according to Carl Trueman, “sees the world as so much raw material out of which meaning and purpose can be created by the individual.”8 Such a view regards human nature as subject to further evolutionary flux, which humans can technologically direct.9

The language of co-creation does not arise from Scripture.

Efforts to blend an evolutionary account with Genesis lead some theologians to argue that humans can “co-create” themselves with God by directing their own evolution, including through HGE.10 Such arguments may cite procreation as an example of co-creation, neglecting that God’s design for procreation does not grant parents any role in consciously determining, customizing, or “knitting together” children. While humans express creativity as image-bearers, the language of co-creation does not arise from Scripture and does not engender biblical conclusions about human nature.11 So, a co-creation model cannot serve as a foundation for thinking biblically about HGE.

Gene Editing Goals and Methods

With these considerations in mind, the next step toward drawing biblical boundaries for HGE is to understand the major goals, methods, and controversies of HGE technologies. Two goals of HGE have traditionally been understood as therapy and enhancement.12 While therapies aim to correct or prevent diseases, enhancements aim to grant “superhuman” traits.13 The line between therapy and enhancement once marked a clear ethical boundary in debates about HGE; however, influential voices have called that boundary into question—usually by pointing to cases where the boundary is unclear.14 But other voices counter that the line between two categories is not always invalid simply because it may be blurred; saying otherwise is a continuum fallacy.15

Further justification for the enhancement-therapy boundary stems from worldview considerations. A secular worldview offers limited grounds for discerning diseased versus enhanced states without either importing teleological ideas or relying on some concept of “normal” as statistical averages within a given species.16 But statistical explanations run into problems since an evolutionary view sees living things as subject to indefinite changes.17 Some changes may be “good” from a survival standpoint, but naturalism cannot provide a foundation for calling them “good” in a morally meaningful way.18 So, naturalists can use the word “normal” to describe a current statistical reality but not to evaluate whether a state is inherently “normal” or “good.” Yet such evaluations are necessary for drawing stable, meaningful distinctions between normal, diseased, and enhanced states.

Therapies mitigate the effects of humanity’s fall, while enhancements mirror the cause of humanity’s fall.

In contrast, the Genesis view of a given, good, but corrupted human nature does provide robust grounds for making this distinction. Identifying a precise definition of disease versus health can become quite complex, surpassing this discussion’s scope. But to the practical degree that we can recognize healthy versus diseased states, we can think of “normal” states as being “those which fall within the range of natural human variation without qualifying as diseased.”19 By this view, normal states reflect God’s given, good designs for humanity, while diseases reflect the suffering inherent in a fallen world. This biblical understanding justifies the goal of healing diseased states, as Jesus modeled. Simultaneously, a biblical view casts moral doubt on attempts to “enhance” humans in ways that reflect discontentment, hubris, or misplaced desires to become “like God” (Genesis 3:5). Put differently, therapies mitigate the effects of humanity’s fall, while enhancements mirror the cause of humanity’s fall.20

The methods for pursuing either goal fall under two categories of HGE: somatic editing and germ-line editing. Somatic editing alters the DNA of cells that will not be passed down to offspring. But germ-line editing alters the DNA of embryos, gametes, or germ cell precursors. Without further editing or mutations, the changes will be passed down through all future generations. While somatic cell editing is already being tested for therapeutic purposes, human germ-line editing is currently banned across many countries.21

The Controversy of Human Gene Editing

With these basics established, we can examine common arguments for and against HGE. Arguments for HGE focus on the perceived benefits of gene editing technologies. For some HGE advocates, these benefits include the possibility of using CRISPR for cosmetic or “enhancement” uses. For example, molecular biophysicist Joshua Zayner seized media attention in 2017 by injecting CRISPR-edited DNA into his arms in hopes of promoting muscle growth.22

Medically, HGE unlocks unprecedented possibilities for treating a wide range of diseases.

Because enhancement and cosmetic applications of HGE remain controversial even in secular bioethics discussions,23 the most influential arguments for HGE focus on medical benefits. Medically, HGE unlocks unprecedented possibilities for treating a wide range of diseases. For instance, treatments that use CRISPR to edit stem cells from bone marrow show promise for treating sickle cell anemia.24 Clinical trials are also underway to test if CRISPR-edited white blood cells will help to treat leukemia.25 Still other studies suggest CRISPR may cure several types of blindness.26

While somatic gene therapies pack powerful promise, some ethicists point out that somatic editing may be less helpful for genetic diseases which impact cells across the body or which start causing damage during prenatal development.27 For these cases, a more effective treatment may be germ-line editing. The classic argument for germ-line editing looks at such a scenario, where two prospective parents want a biologically related child, but both suffer from a recessive genetic disease.28 If germ-line editing to alter a single nucleotide would prevent the disease not only in their child, but also in all future grandchildren, would doing so be wrong?

This is a core question of bioethical debate. Arguments against human germ-line editing—even for strictly therapeutic purposes—address several common topics: safety, unnaturalness, “playing God,” human dignity, consent, “designer babies,” eugenics, and embryo destruction. Thinking biblically about human gene editing will require evaluating each of these arguments from a scriptural perspective.

Evaluating Arguments Against Germ-Line Editing

1. Safety Issues

Regarding safety, HGE is a novel practice with unknown and unpredictable potential long-term consequences.29 Part of this unpredictability stems from the complex nature of DNA, a single section of which may carry multiple layers of information interacting with other molecules and the environment. So, a genetic change that benefits an organism on one level may cause unexpected consequences on other levels. Such consequences from gene editing are known as “on-target” effects, because the editing successfully changed the targeted DNA.30 “Off-target” effects, where changes to DNA occur in ways the researchers did not intend, are also well-documented problems with CRISPR.31 Still another known germ-line-editing problem is mosaicism, where only some of the embryo’s cells end up edited.32

But what if safety were not an issue? Researchers are developing increasingly effective techniques to minimize off-target effects, and mosaicism might be avoided if new methods allow for editing egg and sperm precursors.33 International recommendations currently lean toward allowing therapeutic germ-line editing in the future if safety concerns are addressed.34 A solid ethical case against germ-line editing must therefore stand on more than safety considerations alone.

2. Unnaturalness and “Playing God”

Can we argue that gene editing is inherently wrong because it “plays God” or violates the human genome in a way that is inappropriately unnatural? Secular responses to these arguments often list at least one of six objections.35 First, the phrases “unnatural” or “playing God” are too vague to be practically meaningful. Second, there is no “one human genome” from an evolutionary view, and every human has a slightly different genome that constantly acquires new changes affecting future generations. Third, some secularists argue that humans do “play God” by making decisions with life-or-death implications—for instance, when allocating medical resources. Fourth, humans already manipulate their surroundings, other organisms, and themselves in ways that impact their genes, as when medical breakthroughs for treating otherwise fatal conditions result in higher ratios of disease-associated genes remaining in the gene pool. Fifth, parents frequently make decisions that influence future generations. And sixth, no one would argue that genetic diseases should go untreated because the mutations associated with them are “natural.”

The strength of these objections depends partially on worldview. Regarding the first objection, a biblical mimetic perspective holds that creation does feature certain natural boundaries which are given, good, and inappropriate to cross.36 So, rather than using vague phrases like “playing God,” Christians can more helpfully ask whether specific applications of HGE usurp creation’s givenness in ways that overstep God-given boundaries or inappropriately treat our bodies (or our children’s bodies) as possessions to use however we like.37 A biblical view also weakens objection two, because although humans show genetic variation, we are still one human race sharing a uniquely human array of DNA traceable to Adam and Eve.38

Regarding objections three to five, the fact that humans regularly make decisions which bear life-or-death implications, influence gene ratios, or impact future generations does not tell us which of these decisions are right or whether germ-line editing is ethical. For instance, certain parenting decisions influence future generations in ways that are wrong; could not gene editing do the same? Furthermore, such comparisons are only useful insofar as they are ethically similar. But allocating medical resources, discovering medicines, or making day-to-day parenting decisions hardly equate to intentionally, permanently altering another person’s genetic identity.

Regarding objection six, a biblical—but not naturalistic—worldview provides the basis for affirming that genetic diseases are not natural. So, if only in this respect, a biblical view ironically offers stronger grounds than secularism does for therapeutic germ-line editing. Unless a biblical case can be made that such changes overstep our creaturely boundaries, we need further arguments against germ-line editing before we can rule out all its applications.

3. Human Dignity

One such possible argument is that human germ-line editing represents an affront to human dignity.39 This reasoning packs limited punch within naturalistic frameworks, which see people as biological machines with no inherent, stable, or teleologically meaningful “human nature.” But because Scripture affirms humans as God’s image-bearers, dignity concerns do carry weight in a biblical framework—at least regarding HGE applications that commoditize children or attempt to “enhance” people into “post-human” beings.

Scripture affirms humans as God’s image-bearers.

But even within this biblical framework, it is not obvious that all applications of germ-line editing necessarily violate dignity. Specifically, would changing a gene variant from a disease-causing mutant form to a healthy form in an embryo, sperm, or egg fail to fully recognize a child’s value as an image-bearer of God? It is hard to see why this would be the case, unless the act of changing any gene inherently disrespects some other property associated with being an image-bearer—like having personal volition. This possibility leads us to consent-based arguments against germ-line editing.

4. Consent

These arguments state that human germ-line editing is unethical because a staple of medical ethics is informed consent, but future generations cannot consent to their genes being altered.40 Certainly, consent is too crucial a consideration to ignore. But consent-related arguments may not apply equally across all cases of germ-line editing—especially the classic case where correcting a single mutation can cure a disease. This is because parents cannot normally gain consent from infants for medical interventions, yet few would argue that a cleft palate surgery for a newborn would be wrong because newborns cannot consent. Granted, such interventions affect only the newborns and not subsequent generations; however, the point remains that the impossibility of gaining consent does not always guarantee a medical intervention is unethical.

A related point is that offspring never have been able to consent to their genetic lot. But then, neither do parents naturally have any conscious say in determining their descendants’ DNA. So, putting parents in a position of unprecedented control over their offspring such that parents would need to obtain consent if their offspring could grant it is perhaps the more concerning aspect of germ-line editing.

5. “Designer Babies”

This concern raises further questions: Just how much control would (or should) parents have over their children’s DNA? Should parents be able to not only offer proxy consent for treating current genetic diseases but also opt for genes associated with a lowered risk of future diseases? Should parents be able to customize their children’s physical traits such as eye color or to opt for enhanced or nonhuman traits, if scientific knowledge allows? Will opening the door to therapeutic germ-line editing inevitably lead down a “slippery slope” toward “designer babies”?

A biblical view of children as gifts precludes commoditizing offspring as customizable consumer products.

In answer, society can theoretically avoid slippery slopes if it (1) draws meaningful ethical boundaries between the relevant stages, (2) uses those boundaries to establish practical safeguards, and (3) continuously respects the boundaries and follows the safeguards.41 But these preventative measures rest most stably in the theistic worldview society has rejected. For instance, as discussed earlier, a biblical—but not secular—view provides the grounds for drawing a meaningful boundary between therapies and enhancements. A mimetic view of creation also invalidates desires to “evolve” children toward being anything other than humans. Furthermore, a biblical view of children as gifts precludes commoditizing offspring as customizable consumer products. These points together rule out virtually every germ-line editing application that is not obviously a direct medical intervention to cure a known disease.

Ultimately then, a biblical view does provide grounds for drawing the boundaries society would need if a slippery slope could be prevented. The problem is that humans are fallen, and society does not embrace the biblical principles that provide a foundation for retaining these boundaries. Secular societies can and do draw ethical boundaries but cannot foundationally justify those boundaries. So, a slippery slope may not be inevitable but is foreseeable.

6. Eugenics

Closely related to concerns about “designer babies” is the prospect of eugenics. Pioneered by Charles Darwin’s cousin Francis Galton, eugenics is the “science” of trying to improve the human gene pool.42 Common methods involve encouraging the birth of babies with “desirable” traits or preventing the birth of babies with “undesirable” traits—even by sterilizing or killing prospective parents who bear those traits.43 These latter techniques most famously occurred in Nazi Germany, arousing justified horror which led to the term eugenics falling out of public favor.44 However, modern forms of eugenics still continue as human embryos are discarded or aborted on account of having genes for conditions such as Down syndrome.45

By definition, germ-line editing applications meant to “improve the human gene pool” would involve eugenics. Efforts to “perfect the human race” by engineering genetically “pure” designer babies would most clearly illustrate a eugenics mentality. But arguably, interventions meant to cure a guaranteed disease in a given embryo may not primarily be efforts to “improve the human gene pool.” Still, if this argument is valid, its validity requires the boundary a biblical view establishes between therapy and enhancement. So, whether or not therapeutic germ-line editing counts as eugenics, culture’s widespread rejection of God’s Word places society in a weaker position to resist slipping deeper into eugenics should germ-line editing become legal.

7. Destruction of Human Embryos

From a biblical perspective, no research outcome can justify taking a life created in God’s image.

A final argument against germ-line editing regards the destruction of human life involved. Currently, all germ-line editing relies on in vitro fertilization (IVF), in which human embryos are fertilized in a laboratory environment.46 Typically, the goal of fertilizing these embryos is to implant at least some of them into a mother’s womb. But other embryos, including those which do not show the desired results from genetic tests, are either frozen or discarded. Even some of the implanted embryos may later be selectively aborted, as limited success rates often motivate the implanting of more embryos than can simultaneously develop in one womb. While it is possible to attempt IVF without aborting or discarding embryos, high costs and low success rates make this option more difficult.47 And given today’s widespread lack of a biblical worldview with its respect for preborn humans, combined with an absence of legal rights for humans younger than 14 days post-fertilization,48 IVF techniques and other research procedures required for human germ-line editing would inevitably result in the destruction of countless human individuals.

Objections to this destruction carry less weight in secular frameworks which do not recognize the value of nascent human life. But from a biblical perspective, no research outcome can justify taking a life created in God’s image. Unless the relevant research and technical procedures could occur without destroying (or otherwise harming) human individuals, this destruction presents one of the strongest biblical arguments against human germ-line editing.

Drawing a Biblical Conclusion

In summary, recent advances in HGE technologies demand that Christians respond by drawing thoughtful boundaries based on a solidly biblical worldview.

In summary, recent advances in HGE technologies demand that Christians respond by drawing thoughtful boundaries based on a solidly biblical worldview. This worldview recognizes humans as creatures made in God’s image occupying an orderly yet sin-cursed creation. The importance of alleviating the curse’s effects without overstepping moral boundaries or usurping God’s design suggests that therapy, but not enhancement, is a biblically acceptable goal of HGE. But not all methods of HGE may be ethically equal.

While somatic gene editing for therapeutic purposes seems the least controversial within a biblical framework, germ-line editing raises extra questions. Few arguments against germ-line editing carry weight within a secular view, and not all show equal strength within a biblical view. Still, a biblical view of children as gifts rather than as commodities suggests nontherapeutic germ-line editing is inappropriate. And even therapeutic germ-line editing could foreseeably lead to widespread acceptance of “designer babies” or eugenics mentalities, contrary to a biblical worldview. While a biblical view allows for drawing the therapy-enhancement distinction required to mitigate such risks, society has largely abandoned a biblical foundation. This reality casts serious doubt on the wisdom of legalizing germ-line editing, given humans’ fallen nature.

A more conclusive biblical argument against germ-line editing is the destruction of human life involved.

A more conclusive biblical argument against germ-line editing is the destruction of human life involved. Hypothetically, therapeutic germ-line editing could be accomplished—albeit not very easily—without destroying embryos. The other societal risks of germ-line editing, however, suggest that pursuing alternative medical treatments (including somatic gene therapies) that do not carry these risks is the wisest course of action. Altogether, these considerations highlight how God’s Word remains as relevant for ethical decision-making as ever—even in a world where genetically modified humans are no longer science fiction.