Genetically Manipulated Pigs to Replace Human Organs?

Updated: Jun 21

In January of 2022, the University of Maryland School of Medicine transplanted a genetically modified pig heart into a human. David Bennett, 57, who received the transplant, was not a candidate for a human heart, so the FDA permitted the experimental procedure under the “Right to Try Act.” The first animal heart-to-human transplant occurred in 1984, which was the organ of a baboon. This attempt was like a regular human organ-to-human transplant. However, the animal’s heart was rejected by Baby Fae, and death occurred 21 days later. What made Bennett’s transplant procedure unique was the genetic manipulation of the pig’s heart by human DNA, which raises many moral and ethical issues for Christians.


Transplants from animals to humans are an appropriate use of the creation. Many people eat bacon, ham, and pork chops, so in a sense, hog to human transplants occur every day! At least on the biomolecular level. Some people with diabetes use insulin from pigs, and others receive heart valves from swine. However, the pig heart for Bennett was notably different—it was from a genetically modified pig that used human cells to make a type of human-pig hybrid or chimera.

The genetic modifications of the Bennett pig went beyond the U.S. Agricultural Research Service in Beltsville, Maryland, in 1989. This group inserted a human growth hormone gene into a pig’s DNA. The department of agriculture terminated the trial after the swine experienced joint, lung, and other types of problems. Essentially, however, the genetic manipulation procedure was the same for the Bennett pig. The technique, gene-editing or CRISPR, involved removing four genes from the pig’s genome or genetic makeup and adding six genes from a human to the modified pig zygote. The pig heart for Bennett was created by Revivicor, a biotechnology company linked to a group that cloned Dolly, the sheep, in 1996.

CRISPR (pronounced “crisper”) is shorthand for “CRISPR-Cas9.” CRISPRs are strands of DNA with the protein Cas9. Cas stands for “CRISPR-associated” and “9” the protein. It is an enzyme capable of cutting strands of DNA like a pair of scissors. CRISPR is a molecular tool biologists use to alter DNA sequences to modify gene function. Parts of DNA can be removed from one cell, and pieces of DNA from other cells may be added. The same type of gene editing was used to develop the Pfizer, Moderna, and J&J Covid-19 vaccines.

Genetic alteration has been going on since Adam and Eve conceived Cain, so this itself is a mechanism of God’s providence in nature. Thus, CRISPR is not immoral or unethical. The moral and ethical questions for pro-life advocates stem from where the scientists get the human DNA to manipulate other types of DNA. The Covid-19 vaccines used fetal-cell lines from aborted babies. For the genetically modified pig to create Bennett’s new heart, the six genes were from embryonic stem cells (What are Stem Cells?). Proclaiming life begins at conception is one thing; it is quite another to live it out in practice in our modern world.

Aside from cruelty to animals to produce, harvest, and market pig organs for human use, the more fundamental question for Christians relates to doing evil for a “good” end. According to Romans 12:9, Christians are commanded to oppose evil and affirm good. Terminating the development of a human being in the womb and outside it is evil, and it is equally wrong to use the stem cells of these murdered people to edit DNA. The original act that permitted the harvesting of stem cells disrespected human life and the Creator of life who made it (Is It Moral and Ethical to Use Fetal Cell Lines?).


These matters hinge on the sixth commandment, “You shall not murder,” and of course, one command relates to the entire divine moral law. Since it is written, “For whosever shall keep the whole law, and offend in one point, he is guilty of all” (James 2:10). In John 4, Jesus confronted a woman at Jacob’s well and applied the seventh commandment to her situation, “You shall not commit adultery.” He called her to account for her five lovers. Jesus put the seventh commandment bluntly before her as an uncompromising statement of moral truth with ethical consequences for life.

Shortly after that, Jesus said, “the hour is coming, and is now here when the true worshipers will worship the Father in spirit and truth, for the Father is seeking such people to worship him” (John 4:23). Unlike the legalists and antinomians, Jesus taught the Creator’s law was absolute. Those with his spirit will strive to obey it. According to Jesus, this is to worship the Father in spirit and truth; it is to have an exclusive love for the Creator of life with a sincere desire to obey his moral law in life, even in modern daily living.

When it comes to the sixth commandment and embryos, the lives of unique image-bearers of the Creator were terminated. This issue is central to the use of stem cells and CRISPR technology. Like you and me, embryos were on their way outside the womb and into the world. Unlike you and me, an abortion ended this opportunity for them; this is the issue. Even more sadly, for some, their DNA is engrafted into the DNA of pigs to create organs for those, like Bennett, deemed more worthy to live.


What are Stem Cells?

Like the name “stem cells” infers, these are the root cells of all biological organisms. Bacteria, plants, animals, and humans have developed from these cells. They are sometimes referred to as the tabula rasa of cells. Stem cells contain the DNA or genetic makeup of each unique species, organ, and tissue the cells are designed to create. No other cell in a biological organism can develop new cells to form other types of cells.

As for warm-blooded mammals, embryonic stem cells come into being after a sperm of a male fertilizes a female’s ovum. This is true for hogs and humans. It is from stem cells that specialized cells for the blood, heart, brain, bone, etc., are formed by cellular differentiation, all with their unique functions. According to DNA design, stem cells become specific tissues and organs to facilitate the growth and functioning of the body as a whole. If all goes as planned, the living being will develop in a female’s womb and be born into the world.


While animals and humans have similar biological properties, Suey the pig is not Fred, the human. There is a definite difference between the two species: one is an image-bearer of the Creator; the other is not. While microevolution within a species is a scientific reality, macroevolution from one species to another is a story written by evolutionary biologists. The latter is a belief about human creation, no more authoritative than the one in the Bible. Thus, embryonic human stem cells are different from other mammals and must be treated as human beings in development.


This is important because scientists can create stem cells in a laboratory. One way is by introducing sperm into an ovum from two donor humans outside the female’s body. While the environment will dictate the growth of this embryo, this is still an image-bearer of the Creator in a stage of development. Another way is called “induced pluripotent stem cells,” which are adult human stem cells that can be reprogrammed back into an embryonic-like state. As of 2019, the use of these cells is limited to studying disease models in animals because they are known to cause cancer. The final way is using embryonic stem cells from aborted babies and fetal cell lines, which are by far the most common stem cells used today for gene editing.


Is It Moral and Ethical to Use Fetal Cell Lines?

There are two arguments in favor of using fetal-cell lines for CRISPR procedures. The first is the reproduction of stem cells in labs over decades. Thus, some people will argue that these fetal cells have divided to the point where they no longer resemble the original person. The second is more pragmatic and crasser. Even though the initial act to terminate life was wrong, it’s a shame not to use these embryos for the greater good of society. After all, proponents say, many immoral and unethical medical procedures in the past benefit us today.


Let’s consider a hypothetical situation called the Lost Room of Auschwitz. While touring the concentration camp, a tourist happened to lean against the wall. After doing so, a brick was depressed, and a door opened to reveal a secret lab. The room had several walk-in freezers and a lot of technical equipment still running! The tourists gazed into the illuminated space in disbelief, and the tour guide quickly notified the German authorities. An investigation followed.


The room was a Nazi World War II lab, and inside the freezers were the bodies of prisoners on life support. Files revealed who these people were, how they were captured, and the medical procedures. The crime of the prisoners was their Jewish ethnicity; they were unwanted by the Nazis. Each had a surgery that permanently anesthetized them. Then the temperature of their bodies was lowered to preserve their organs and tissues. There were also instructions explaining how to revive them for future transplant procedures. A team of doctors followed the rewarming instructions for Samuel, one of the prisoners, to see what would happen. His body revived! Icy white faded from his complexion, and he was warm to the touch after several hours. He was no longer hypothermic. According to the instructions, Samuel was now ready for harvesting.

Is Samuel a different person? No.

Even though Samuel is nearly a century old and permanently anesthetized, he is still the same person. Since life begins at conception, which science has proven, the fertilized ovum is a person too, and the stem cells harvested are from that unique individual in a stage of human development.

Should Samuel and these other Jews be used for organ transplants? No.

Imagine the worldwide outcry if something like this happened! Nevertheless, some will undoubtedly argue: “Although it was an awful tragedy, why not permit the transplants to address the organ shortage?” For Christians, however, this is not moral or ethical, nor is it to use fetal-cell lines for society’s “greater good.”


UPDATE: Mr. David Bennett Sr. has sadly passed away due to complications from receiving his xenotransplanted heart. Mr. Bennett's death was caused by a porcine cytomegalovirus, a pig virus that was within the heart he received.


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