Is it kosher to play God with our genes?

A segment on last Sunday’s edition of the CBS newsmagazine “60 Minutes” provides an excellent vehicle to explore the challenges that some major scientific breakthroughs pose to halachic decisors and Jewish ethicists. The breakthrough in this case is known as CRISPR, an acronym for Clustered Regularly Interspersed Short Palindromic Repeats.

CRISPR (or, more accurately, CRISPR/Cas9) contains an enzyme known as Cas9, which can cut through DNA like a pair of scissors. CRISPR also contains what, in essence, is a guidance system that directs Cas9 to the location on the gene sequence that has to be removed. CRISPR thus allows scientists to edit sequences of genes for any number of purposes. It has amazing potential to eliminate certain diseases, from certain cancers, to Parkinson’s, to muscular dystrophy, to heart disease, to a host of other ills, especially those that are genetically transmitted from parent to child.

Several years ago, CRISPR allowed Chinese researchers to edit out a portion of a gene called myostatin from two beagle embryos. Myostatin limits muscle growth. With the myostatin gone, the edited embryos developed into two beagles that are bigger and stronger than other beagles.

Some people would argue that altering DNA is playing with Creation itself. At one point in the “60 Minutes” piece, the segment’s reporter, Bill Whitaker, was speaking with Shoukhrat Mitalipov, who runs the Center for Embryonic Cell and Gene Therapy at Oregon Health and Science University. Mitalipov is considered somewhat of a maverick in the field, Whitaker explained, and he “regularly makes headlines with his innovative, sometimes controversial methods to prevent genetic disease.”

Said Whitaker to Mitalipov, “Your critics say that you’re playing God.”

“I think — you could say to — to every treatment that they — humans and doctors develop that — we — we’re playing God,” Mitalipov responded. “God gave us brains so we could find a way to eliminate suffering of human beings. And if that’s, you know, playing God, I guess that’s the way it is.”

Not every researcher, though, is willing to be that bold when it comes to tampering with the human genome. Feng Zhang, a researcher at the Broad Institute in Cambridge, Massachusetts, has been working on CRISPR for the last seven years. “We don’t really understand how complicated biology is,” he told Whitaker. “There’s a gene called PCSK9. If you remove PCSK9, you can reduce cardiovascular disease — heart attack risks — significantly. But it also has been shown recently to increase risk for diabetes. So how do you make the judgment call between these tradeoffs? And there will likely be other impacts we haven’t yet identified. So I think we need to wait and be more cautious.”

Rabbinic literature made this point nearly 2,000 years ago. “Our Rabbis said: Even those things which you may regard as completely superfluous to the creation of the world, such as fleas, gnats, and flies, even they too are included in the creation of the world, and the Holy One, blessed be He, carries out His purpose through everything….” (See Midrash B’reishit Rabbah 10:7.)

More to the point is that everything has its point, its reason for being, according to Rav Yehuda, quoting the sage Abba Arikha (he is better known as Rav). God “did not create…[anything] for no reason. He created a snail as a remedy for a sore; He created a fly to be crushed, and spread as a remedy on a wasp sting; He created a mosquito as a remedy for a snake bite; and He created the snake itself as a remedy for a skin rash; and He created a gecko as a remedy for a scorpion bite.”

By way of a more sound scientific example of this, let us consider invertebrates, which the midrash just cited said might be seen among “those things which you may regard as completely superfluous to the creation of the world.” Many invertebrate species are at risk of extinction. So what? Would not the world be a better place without most of the invertebrates? Do we really need more wasps, or bees, or flies, or even butterflies, for that matter, or coral reefs?

Actually, invertebrates do a lot for us. Some are a vital source of food for birds, fish, humans, and other animals. Some help create food by pollinating flowers, which then turn into fruits, berries, nuts, and seeds. Some species are vital to agriculture because they have a unique ability to aerate soil, thus helping to boost the growing potential of that soil. Others, because they feed on fungi, bacteria, and decaying carcasses, turning them into compost, provide nourishment to the soil, while also helping to clean up the environment. Some even play a role in pest control, even though many are considered pests themselves.

Before anyone fiddles with a gene to remove or alter it, then, it would be helpful to know if there is the kind of tradeoff Feng Zhang noted regarding PCSK9 — limiting a person’s risk for a heart attack by making that person more likely to develop diabetes.

This, then, brings us to the two basic questions facing halachists and ethicists: Does Jewish law allow for tampering with the genetic code, at least without any clear understanding of where that may lead? And even if the law would allow such tampering, is it ethical to do so?

Torah law, it would seem, would prohibit gene tampering (see, for example, Leviticus 19:19). On the other hand, based on Leviticus 18:5, Torah law makes preserving life the prime directive, thereby overriding nearly all of its other rules. The Torah, for example, prohibits causing harm to an animal, but anything “that is necessary in order to effect a cure, or for other [beneficial] matters, does not entail [a violation] of the prohibition,” according to Rabbi Moshe Isserles’ gloss to Shulchan Arukh, Even Ha-ezer 5:14. Nevertheless, Isserles suggested that people refrain from causing such harm because it “constitutes cruelty.”

A contemporary halachist, Rabbi Moshe Dovid Tendler, also is a distinguished biologist. In 1999, he testified before the United States National Bioethics Advisory Committee on the acceptability of stem cell research. “Even biblical law is superseded by the duty to save lives, except for the three cardinal sins of adultery, idolatry, and murder….Mastery of nature for the benefit of those suffering from vital organ failure is an obligation. Human embryonic stem cell research holds that promise.”

For the purpose of this discussion, the key phrase in his statement is “mastery of nature.” Mitalipov is correct in saying “God gave us brains so we could find a way to eliminate suffering of human beings.” Feng Zhang, however, is equally correct when he says, “We don’t really understand how complicated biology is.” After all, as Rav Yehudah said in Rav’s name, God “did not create…[anything] for no reason.”

God has revealed some of the secrets of Creation, and CRISPR surely is one of them, just as the genome itself is. These are His revelatory gifts to us, and we should make full and good use of them. First, though, we need to be certain that we will not lose more than we will gain.

About the Author
Shammai Engelmayer is rabbi emeritus of Congregation Beth Israel of the Palisades. He hosts adult Jewish education classes twice each week on Zoom, and his weekly “Keep the Faith” podcast may be heard on Apple Podcasts, iHeart Radio, and Stitcher, among other sites. Information on his classes and podcast is available at
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