Credit: National Inst. of Health

Introduction

The manipulation of our genes is a new and rapidly developing process for addressing genetic disorders of the kind we have discussed in “Jews and Genetic Disorders.” What if medical science could develop safe and effective procedures to eliminate variant (or other unwanted) genes from our bodies and replace them with normal (or other more desired, if not objectively better) genes? Engaging with gene-altering technology raises a host of practical questions each and all of which also invoke ethical considerations. A Venn diagram which included areas at least for medical, political, economic, and ethical areas of concern might illustrate the general complexity of the matter, but we need more than a picture to get to the nits and grits of the subject.

Jews may have a unique perspective from which to begin our investigation. We have been talking about health matters for over 2,500 years, and have, based on our religious texts and traditions, and our experience, developed a useful orientation, or, perhaps better, a useful conversation for considering the challenges of human gene editing.

As we have discussed elsewhere with respect to vaccinations, the origin of any Jewish ethical approach has its beginnings at the very start of the Jewish Peoples’ origin story. We don’t have to go all the way back to the pre-creation state of chaos, just to the first report of the creation of humankind. There we are told that humans were created by a Supreme Being and made b’tzelem Elohim, in God’s own image. (Gen. 1:27.) Rabbi Danny Nevins, of the Jewish Theological Seminary, acknowledges that this phrase is ambiguous. Moving beyond any notion of physical similarity, though, Rabbi Nevins holds that it at least “implies that humanity has God-like qualities and therefore great responsibilities.”

Having created them, the Master of the Universe wasted no time in issuing God’s first commandment to the humans: “Be fruitful and multiply, and fill the earth and subdue it and dominate . . . every animal . . . on the earth.” (Gen. 1:28.) Of course, according to the Torah, the first generations of humans proved to be a disappointment, so those living at a particular moment met a watery demise (Gen. 6:5-7:23), but God reportedly tried one more time with a fellow named Noah and his sons. And once again, after the flood waters had receded, and the chosen family (Beta version) was safe on dry land, they were directed to “(b)e fruitful and multiply and fill the earth.” (Gen. 9:1, 7.)  This new group of humans was also told that all the animals of the earth were “given into [their] hand(s).” (Gen. 9:2.)

According to Rabbi Nevins, Jewish tradition has evolved into two camps of thought: a preservationist camp and an interventionist camp. The preservationist camp is grounded in a priestly tradition that perceived a divine sense of order and understood distinctions between kinds of things to be the essence of holiness. They saw the world as comprised of things clean and unclean, with conduct permitted and prohibited. Consequently,  preservationists are interested in maintaining order as they understand it and the borders that protect and preserve it.

The biblical prohibition in Leviticus (at 19:19) against mixing different kinds (kilayim) is one example of this approach. There we find a prohibition against letting cattle mate with other species, against sowing two kinds of seed in the same field, and against wearing clothing made with two kinds of yarn. And, so, some authorities would prohibit gene therapy based on the kilayim doctrine, while others have rejected the applicability of that approach.

But why should God, or mere mortals, even care about such things? Because, wrote the 13^th Century Spanish rabbi and physician Moses ben Nachman, also known as Nachmanides or by the acronym Ramban, the grafting of species suggests either that God did not complete the work of creation, or worse, that God created an imperfect world. In either case, the process of mixing together separate things alters and undermines God’s work.                      

In short, the preservationists stress the importance of the sacredness of life and the context in which God placed it, according to the Torah as they read it. For interventionists, to disrupt those original borders, to change the nature of a species, to remake what we have been given in order to satisfy some human need or desire, is not only unauthorized by the Creator, but presumptuous and arrogant, and, needless to say, forbidden. For them, altering the arrangement of creation demonstrates a lack of faith in the Creator. So, naturally, they are wary about some people “playing God” by tampering with nature.

When considering the “tradition,” though, we have to be careful about selecting our sources, our precedents. For instance, if Ramban was concerned about interfering with nature, he also could be read to have limited his concern to insuring the maintenance and preservation of a species. Beyond that, he understood all of life to be “a window on divinity,” and that re-creation was a power to be encouraged. Whether or not that reading is accurate we need not decide, because it would seem that the interventionists have been and remain the dominant voice throughout recorded Jewish history. 

As Rabbi Nevins has explained, interventionists, too, stress the sacredness of human life, but they understand those early injunctions to the Adam and Noah families as a call to stewardship. Thus, they echo the psalmist who characterized humans as “a little less than Divine, and adorned with glory and majesty,” indeed, made by God as and to be “masters” over God’s handiwork. (Psalm 8.)

In more modern times, Joseph Ber Soloveitchik (1903-1993), a preeminent American Orthodox rabbi and Jewish philosopher, thought that the very fact that the Torah talked about creation was itself a lesson, specifically “that man is obligated to engage in creation and the renewal of the cosmos.” Moreover, Soloveitchik considered humankind to be a “partner” with the Creator with the purpose of “finish(ing) the creation process.”

Soloveitchik was hardly a modern-day revisionist. Interventionists can boast of a long intellectual lineage. Like preservationists, the interventionists’ approach begins long ago, but interventionists depart from the preservationists’ premise that the world created by God was both perfect and complete. In their view, the negative commandment found in the Torah to refrain from wounding oneself (Deut. 14:1, Lev. 19:28) and the positive commandment to take exceeding care of oneself (Deut. 4:9, 15) can be seen as dual acknowledgements of possible or potential imperfections and calls to do better.

Similarly, the negative commandment to not stand idly by the blood of your neighbor (Lev. 19:16) and the positive commandment to make a parapet around your roof of your house to guard against accident or injury (Deut. 22:8) underscore the obligation to act. Surely, interventionists might ask, how else is one to behave if one is to love one’s neighbor as oneself? (See Lev. 19:18.)  

Legal requirements to intervene emerged as moral imperatives in the Talmud, a collection of commentaries from the first millennium of the Common Era. Among many discussions concerning the value of life are two oft-cited concepts that reinforce one another: 

• The basic, if poetic and hyperbolic, understanding is that if anyone were to take a life, it would be as if he destroyed a whole world, but if anyone were to save a life, it would be as though he saved a whole world.
• The overriding principle is that of pikuach nefesh. It holds that all of the commandments, laws, regulations, and rules of Judaism – with three exceptions (idolatry, murder, improper sexual conduct) – can be disregarded to save a life.         

Subsequent rabbinic interpretations in the Middle Ages emphasized the importance of both guarding one’s health and guarding against disease.  For instance, the 12^th century Spanish-born physician and philosopher Moshe ben Maimon, also known as Maimonides or Rambam, wrote that Jews have a positive duty to use proactive measures to protect against a foreseeable harm. Similarly, the 16^th Century legal scholar and codifier Joseph Karo stated that Jews have a religious obligation to take affirmative steps to prevent an anticipated danger to themselves or others.

These texts and traditions can be boiled down to two fundamental responsibilities all Jews have. One is for self-care. The other is to sustain members of the community.

Thus, interventionists are willing to utilize human intelligence and ingenuity, also seen as gifts from God, in order to both prevent and ideally cure disease, thereby improving the quality of a person’s life and extending its duration.

While you may have an instinctive regard for one camp or another, each must deal with serious problems. The preservationists have to explain why a safe and effective technology (our premise) ought not be employed to reduce pain, eliminate disease, and preserve and prolong life. Do they really believe that God, said to be full of compassion and abounding in love (Ex. 34:6-7), wants us to sit still while a mutant gene brings avoidable misery to a person made in God’s image?

The issues confronting the interventionists are quite different. After all, if CRISPR or other gene editing therapies can save lives, then, quite plausibly, those involved in developing, utilizing, and facilitating those therapies are not “playing God,” rather, they are acting well within the prime directive of pikuach nefesh. As Rabbi Nevins has written, the natural environment in which we live is not static, but dynamic, “and adaptation is the key to survival.” Consequently, he contends, “(i)f new therapies are invented which can prevent disease and enhance life, then they would be not only permitted but even required.”

To these broad philosophical considerations, Rabbi Azriel Rosenfeld (1931-2004), both a rabbi and a pioneer in digital image analysis, has supplied a technical point. Observing that the gene editing process involves particles that are invisible to the naked eye, he has argued that no such process is forbidden in Jewish law. A similar approach was part of the reasoning behind the determination that certain vaccines were not treif (forbidden), although they contained cells of non-kosher animals, and that crops of genetically modified seeds were permissible to eat.

The Challenges that Confront Us

Still, while the interventionists may have an easier time than the preservationists with the initial question regarding the propriety of intervening at all, the challenges for the interventionists are, if anything, much trickier because they are not just about whether to act, but about when, under what circumstances, and to what extent intervention is at least appropriate, if not required. We consider below a non-exclusive selection of nine such challenges.

The challenge of disease selection

While there is some disagreement about how may gene mutations may give rise to a genetic disease, either alone or in combination with other genes or factors, there is strong agreement that there are thousands of possibilities for genetic malfunctions. Some of these situations are well known today and affect tens of thousands of people every year. Some are lesser known, if known at all, outside of the population of the relatively few poor souls who are directly affected and their families. Assuming limited resources, about which more in a moment, should the focus of medical intervention be directed to curing the disease which affects the most people? Or should it be directed to treating the diseases with the greatest frequency of fatal outcomes or the most debilitating outcomes?

Presently, there is no centralized authority or system that decides what diseases should be studied, by whom, where, and when. Who or what entity should select the conditions to be addressed? Should the decider be a public entity or a private one? What process will open the door to the most productive scientific discovery? What process will focus or foreclose scientific inquiry and medical applications?

The challenge of sufficient medical personnel and facilities

What might happen if all necessary resources were devoted to the treatment of just one genetic disease, such as sickle cell disease (SCD). How many clinics would be required to treat all those tens of thousands who need assistance? How many doctors and specialized teams would need to be assembled to provide the therapy? Who would be available to cover the important work they were doing before concentrating on SCD?

The challenge of patient selection

Whether or not we limit available resources to focus on certain genetic disorders, how should patients be selected for approved novel therapies, however they are approved? And among the many candidates who have a potentially treatable condition, who selects the individuals to be treated?

With medicines or procedures which have been used for an extended period of time, we have a data base that might indicate the likelihood of a successful treatment program. But with novel therapies, do you start by admitting only the youngest with the longest potential survival period or the oldest who cannot wait too long for treatment?

The challenge of affordability

Of course, patient selection could be based on the patient’s ability to pay for treatment. But, as we have seen previously, the current costs of CRISPR therapies appear to be beyond the ability of the vast majority of individuals who could benefit from them. A recent story highlights the potential benefits of such technology and the challenge of affordability.

In May, 2025, the New England Journal of Medicine reported about an apparently successful use of a “personalized base-editing therapy” developed with CRISPR technology to treat an infant born with a disorder considered to be ultrarare in the United States, as it affects just 1 of every 1.3 million infants. The gene at issue was CPS1 in chromosome 2, a gene which facilitates the making of an enzyme that is supposed to help remove excess nitrogen early in the urea cycle before the urea is excreted by the kidneys. When it cannot do so, the nitrogen accumulation can lead to the formation of ammonia with potentially deadly results.

Not only did a gene therapy have to be designed for the baby, but a collaboration of involved parties including a hospital, doctors, and biotech companies had to be mobilized and agree to proceed for no or considerably reduced compensation. That they did so within just a six months period after the baby’s birth is remarkable. As of this writing, we do not know how the initial contacts were made or how negotiations proceeded. Perhaps the challenge was a sufficient driver. Perhaps anticipated notoriety was a motivator. In any case, today, one infant and one family can rejoice, but others facing similar problems probably should not count on receiving similar results.

On the matter of affordability, the Torah indirectly offers one consideration. The Holiness Code teaches that we should neither favor the weak, nor defer to the great. (Lev. 19:15.) That is, a person should not be favored or disfavored due to economic status. Here the Torah is speaking in the context of legal judgments, but if the scales of justice ought not be tilted due to social position or financial condition, should access to health care be similarly immune to such considerations?

There are at least two responses to that question. The first suggests that the premise is faulty. While some might wish it otherwise, in the United States, the legal system and practice of medicine are not the same. In the former, justice is viewed as a goal applicable to different members of society who are of equal political status subject to laws enacted by their representatives and the resolution of disputes in public courtrooms. In such a system, it is in the interest of the governed, the governors, and society in general that everyone has a clear right to be judged without regard to their wealth or station.

By contrast, and again recognizing that some wish it were otherwise, all medical treatments in the United States are not at present provided by government employees in government facilities. They are largely, if not exclusively, handled privately. As a practical matter, the American legal system has the personnel and facilities to handle a wide variety of legal matters across the nation in a generally satisfactory manner. Our medical system can make no such claim.

The second response recognizes that enabling a rich person to pay for medical services not otherwise available does not necessarily deprive of poor person of those services (because the poor person would not receive them in any case) and may, in addition to improving medical knowledge, lead to a subsidization of more services for the poor, if the charges to the rich person are so calculated. By analogy, the fact that certain billionaires can access a trip into space, while the other 99%+ of us cannot does not mean that we are being treated inequitably any more than the fact they can live in palatial estates, while the rest of us cannot, means that they should not be able to live where they want.

To think otherwise is to believe that our individual ability to live our lives as we choose ought to be limited to some level achievable by all or, at least, the vast majority. Nothing in Torah suggests such an outcome. To the contrary, the recognition that the poor will always be around was made expressly in Deuteronomy. (See Deut. 15:11.) That reality was repeated centuries later in the Christian Bible in multiple Gospels. (See Matt. 26:11, Mark 14:7, John 12:8.) Moreover, in the Hebrew Bible the recognition was not made approvingly, but as a spur to help the less fortunate. The greater societal problem regarding genetic treatment then is not whether one group, or even one patient, should be favored over another, but the affordability of health care generally, an issue well beyond the scope of this discussion. Nevertheless, we must touch on it. This leads, naturally enough, to the challenge of economics.

The challenge of economics

Now that we have, or are on the verge of having, this fantastic new technology, who pays for all these treatments? In 2023, spending on health care in the United States alone reached about 4.9 trillion dollars, just under 18% of the nation’s Gross Domestic Product. That is a cost of $14,570 per resident. As the reported costs of initial CRISPR treatments for sickle cell disease demonstrate, these new therapies are quite likely to be out of the economic reach of most patients even with a private health plan as the plan may not cover such treatments or may have restrictions or limits making coverage questionable. 

One recent study ran a series of simulations to estimate the increased costs, again in the United States alone, of new gene therapies. One conclusion was that the additional cost to the health care system would amount to just over 25 to 20 billion dollars a year from 2026 to 2030. The numbers, while high, do not represent a large increase in the total national healthcare system, but that system is under stress now sufficiently so that this increase may be the proverbial straw that breaks it.     

Moreover, while the study projected out increased therapies and patient treatments, it did not explain where the new hospitals or additional doctors or nurses would come from to handle the increased patient load, regardless of the therapy that is needed.

If we are not content to muddle along, how can we incentivize more people to enter into the medical professions to provide the care we want? And how can we assure them that we won’t withdraw our early incentives once they commit to our program? If care is not to be available only to those who can afford it, what kind of social investment is required and from whom?

The challenge of non-healing enhancement

If, as Rabbi Nevins has noted, successful gene therapies could prevent disease, or obviously, if they could cure disease, then a patient’s life would be enhanced, that is, improved, strengthened, made better.

But there are enhancements and then there are enhancements.

What if gene therapy could be used to select eye or hair color, or height or strength, or artistic aptitude, or intelligence? Assuming that a procedure for trait selection or enhancement would not modify any pathological gene or provide any clear medical benefit, but would improve, perhaps optimize, one or more capabilities, would such a procedure be permissible under Jewish law, tradition, or ethics?

Traditional authorities seem to be split about trait enhancement. One side argues that the Torah does not permit physicians to perform a non-healing act and, moreover, that wounding oneself for no medical benefit is specifically prohibited. On the other hand, some see current and common practices like cosmetic surgery, especially for individuals with abnormal features, and ear piercing or hair dyeing, as being relatively risk free and a permissible way to address a patient’s concerns about appearances for reasons related to acceptance in employment, social situations, or, even, spouse selection.

Parenthetically, if non-healing enhancements were permitted, does that exacerbate, or at least complicate, prior considerations regarding patient selection or financing? Should private funding be allowed for such procedures if such activities were to utilize personnel or spaces that could be used  to treat those with more medically serious, even debilitating or deadly, infirmities? Should public funds be employed to such situations while there are not sufficient funds to alleviate, maybe prevent, genetic anomalies that cause pain and suffering?

For his part, Rabbi Nevins sees the distinction between therapy and enhancement as “highly problematic.” Though concerned about society’s current regard for “beauty and physical prowess” as well as economic class divides and access to new technologies, he thinks that “most people” would value more resilient bodies and more vibrant minds and, so, would permit such enhancements as long as the sanctity of life is not undermined.

But given the biases we have seen, and still see, related to human appearance traits from the color of one’s skin to one’s height, or lack of it, or one’s weight, or the amount of it, even the shape of one’s eyes or nose or the texture or display of one’s hair, it’s not too hard to imagine problems. If a society were to idealize a particular look, and that look were attainable though gene editing, over time would not those who could not or would not conform be subjected inevitably to some form of invidious discrimination? Would not that development then lead to a commoditization of the human species? And would not the marvelous and glorious diversity of humankind, each and all made, according to our tradition, in the image of God be constricted and doomed to exist in a drab monoculture?

The challenge of generational change   

If you think these are complex and difficult questions, you would be right, but as Al Jolson said about a century ago, “You ain’t heard nothin’ yet.” Questions related to the treatment of individuals are easy compared to the next set of challenges because intervening on behalf one person, while extraordinarily valuable for that person, does nothing to prevent the transmission of a mutated gene to the next generation, either to prevent a disease from recurring or to enable an enhancement to be transmitted.

To do that, you have to edit a reproductive cell, that is, a sperm or egg cell, or a very early-stage embryo.  This is known as germline editing. The result here will affect not just one person, but generations to come. Indeed, should the process be applied to enough people, an entire society could be changed.

With germline editing, the blessings and curses of biotechnology are multiplied. If a disease can be eradicated, that would surely seem to be beneficial. If a certain segment of a population were bred tall and strong and of a certain color, perhaps not. Transgenerational trait selection could lead to uniformity of looks and disvalue not just defects or anomalies but mere differences. If your interventionist head is spinning, you might want to rethink the preservationist perspective.

And we can even go down the interventionist rabbit hole a bit further. But for every good question, there is a fair rejoinder. For instance:

Q. What right does one person today have to affect generations to come?

A. While it is true that our enhanced progeny might someday contend that they did not agree to be enhanced, it is also true that descendants generally have not consented to be created pursuant to any parameters. After all, one has to be at least alive in order to make a determination about consent and those not yet conceived, let alone born, obviously are not so qualified. Nor is an early-stage embryo competent to make a reasoned decision about enhancement.

Q. What, if any, effect might the absence of debilitating disease have on individual or societal psychology, especially empathy?

A. A similar challenge could have been raised with respect to new techniques for farming. Would they alleviate hunger or lead to excessive populations? But why should our inability to project future behavior with precision be an impediment to helping people now and protecting their biological legacy?

Q. Can we ensure that the process won’t worsen existing disparities in economic or other classes?

A. Ensuring against undesired consequences of scientific breakthroughs is a high bar. There are often unintended consequences when, and whether, society acts or fails to act. History suggests, though, that scientific advancements, like vaccines, can help considerable numbers of people. So, the important question really is whether the risks inherent in genome editing can be managed, at least for particular conditions for which there are no currently available cures.

The challenge of speculation and abuse

It is a truism that we do not know what we do not know. Among the things that we do not know, as Donald  Rumsfeld once observed, there are known unknowns and unknown unknowns. For instance, we know enough to acknowledge that we don’t know about the causes of many genetic disorders, but we do not have sufficient data about the long-term safety and efficacy of emerging technologies to know what, if any, problems we may encounter. So, speculation about a world free of genetic imperfections could lead to either dystopian or utopian societies.

Still, the concern here is not academic. Given the horrendous effort of 20^th Century Nazis to claim that Jews were generally inferior beings, and therefore subject to annihilation, Laurie Zoloth, a Jewish bioethicist, argues that “Jewish bioethicists are bound to a particular attention to the possibility of genetic abuse.” But concern is not data either. When dealing with the future, we just don’t know all that we don’t know.

Of course, we can and should do what is possible and practical to make sure that proposed therapies are safe and effective, and that access to them is not prohibited due to factors that are invidiously discriminatory, but there is no ethical principle that permits rank speculation about a conceivable distant future harm to override the clear and present medical danger that might be alleviated today such that people whose health might be improved or lives saved would not receive needed treatment.

The challenge of species stewardship

All species have within them a drive to preserve their existence, to perpetuate the species. In its initial stage, evolution accommodated this compulsion by rewarding the fittest of the species, meaning those organisms that best adapted to the environment in which they found themselves. A second stage was born when humankind learned how to modify, as well as adapt to, a variety of environments. Bioethicist Paul Root Wolpe has taught that we are now entering a new age of evolution. This new third age, according to Wolpe, will be inaugurated by our new found ability to alter not just our surroundings, but ourselves.

Believing that this new technology, as potentially applied to germline editing, is neither safe nor effective, as well as not needed, leading scientists have questioned whether it should be allowed and even occasionally called for a moratorium on for instance, gene-edited babies. But such calls have not ended the controversy.

Conclusion

Early in the book of Genesis in the Hebrew Bible, we are provided with an explanation, two actually, of the origin of humankind.  Ultimately, we are told that a man and a woman were placed in a wondrous garden called Eden and, as noted above, were directed to subdue the earth and dominate life on it. (Gen. 1:28.)

They were, however, expressly forbidden to eat the fruit of the tree of knowledge of good and evil located in the center of the garden. (Gen. 2:17.) According to the story, the man and woman disobeyed and were expelled from the garden. The motivation of each of the characters in the story can and indeed has been debated for thousands of years, but one thing is crystal clear: neither the man nor the woman nor any of their descendants ever returned to the wondrous Eden.

Since the dawn of our species, in reality as well as in literature, we have been engaged in a continuous search for new knowledge and the application of what we have learned. Moreover, once our species gains certain knowledge, it rarely forgets what it has learned and in fact tends to build on that information, although, for sure, it may from time-to-time misapply the knowledge gained.

You might say that this drive for knowledge is part of our DNA. What is certain is that we will never return to Eden. Nor should we want to do so. The technology of human gene editing is a new branch on the tree of knowledge. And It holds out both the promise of good and the peril of evil for our species. We should neither forgo our study of this new branch nor abandon our concerns about the appropriate use of any new knowledge gained. And we must learn how to deal with the resulting tension.

The conflicting possibilities of germline editing were underscored recently when in late March, 2025, a number of individuals involved in various aspects of biotechnology issued another call, this time for a ten-year moratorium on germline editing. Then, less than three months later, a cryptocurrency billionaire announced his intent to fund the exploration of embryo editing with a new base editing technique that might be safer and cheaper than CRISPR. Base editing is different than germline editing, but, not surprisingly, the American public is “closely divided” about whether any editing of a baby’s genes is appropriate, with significant numbers regardless of gender or educational status simply “not sure.” Whatever your views may have been, it seems clear that we are in for a fascinating conversation. Buckle up.

Like the Webb space telescope and the Hubble before it, CRISPR technology is engaged in incredible new research, plus it is making amazing new therapies possible.  But where Hubble and now Webb have taken us deeper into space allowing us to see previously unknown aspects of our universe, CRISPR and other biotechnologies are allowing us to reach deep inside our bodies, into our genetic code, raising the possibility of treatments and even cures for devasting disorders. Given its vastness, and its inaccessibility, space may remain a distant final frontier. But the door to our genome, our genetic essence, is just opening now and it promises to be enormously beneficial if we are wise and prudent.

As the Torah closes, we are told that the leader of the Israelite nation summons his strength to provide final lessons to his people. He reminds them about the blessings and curses that lie before them, and about the choices that they can and will have to make. He says, in words that might well apply to CRISPR and other new biotechnologies, this is not a trifling matter, it is your very life.  (Deut. 32: 45, 47.) Now, as then, the impulse must be to choose life. And that impulse must drive society to figure out the details of the equitable application of these amazing medical advances, sooner rather than later, for as Hillel asked long ago, “if not now, when?” (Pirke Avot 1:14.)