Genetic Engineering

The MSPCA believes scientists’ ability to clone animals, to alter the genetic makeup of an animal, and to transfer pieces of genetic material from one species to another raises serious concerns for animals and humans alike.

This page will explore issues related to genetic engineering, transgenic animals, and cloned animals. It will examine the implications of genetic engineering on human and animal welfare and will touch on some related moral and ethical concerns that our society has so far failed to completely address.


  • Genetic engineering is the science of modifying the genetic material of a cell or living organism to produce a new trait in that organism or to make a biological substance such as a protein or hormone.
  • A transgenic animal is one whose genetic makeup has been modified through genetic engineering.
  • “Cloning” refers to a procedure known as somatic cell nuclear transfer (SCNT). To clone an animal, the nucleus – which contains the genetic material – is removed from an unfertilized egg and replaced with the nucleus of an adult cell from the donor animal to be cloned. This resulting offspring is an animal that is an almost exact genetic copy of the donor, though some differences remain.

Problems related to the physical and psychological well-being of cloned and transgenic animals, significant ethical concerns about the direct manipulation of genetic material, and questions about the value of life itself must all be carefully weighed against the potential benefits of genetic engineering for disease research, agricultural purposes, vaccine development, pharmaceutical products, and organ transplants.

Genetic engineering is, as yet, an imperfect science that yields imperfect results.

Changes in animal growth and development brought about by genetic engineering and cloning are less predictable, more rapid, and often more debilitating than changes brought about through the traditional process of selective breeding.

This is especially apparent with cloning. Success rates are incredibly low; on average, less than 5% of cloned embryos are born and survive.

Clones are created at a great cost to animals. The clones that are “successful,” as well as those that do not survive and the surrogates who carry them, suffer greatly. Many of the cloned animals that do survive are plagued by severe health problems.

Offspring suffer from severe birth defects such as Large Offspring Syndrome (LOS), in which the cloned offspring are significantly larger than normal fetuses; hydrops, a typically fatal condition in which the mother or the fetus swells with fluid; respiratory distress; developmental problems; malformed organs; musculoskeletal deformities; or weakened immune systems, to name only a few.

Additionally, surrogates are subjected to repeated invasive procedures to harvest their eggs, implant embryos, or – due to the offspring’s birth defects – surgical intervention to deliver their offspring. All of these problems occur at much higher rates than for offspring produced via traditional breeding methods.

Cloning increases existing animal welfare and environmental concerns related to animal agriculture.

In 1996, the birth of the ewe, Dolly, marked the first successful cloning of a mammal from adult cells. At the time of her birth, the researchers who created Dolly acknowledged the inefficiency of the new technology:  it took 277 attempts to create this one sheep, and of these, only 29 early embryos developed, and an even smaller number of these developed into live fetuses. In the end, Dolly was the sole surviving clone. She was euthanized in 2003 at just 6 years of age, about half as old as sheep are expected to live, and with health problems more common in older sheep.

Since Dolly’s creation, the process of cloning has not demonstrated great improvement in efficiency or rates of success.  A 2003 review of cloning in cattle found that less than 5% of cloned embryos transferred into surrogate cows survived; a 2016 study showed no noticeable increase in efficiency, with the success rate being about 1%.

Currently, research is focused on cloning for agricultural purposes.  Used alone, or in concert with genetic engineering, the objective is to clone the “best stock” to reproduce whole herds or flocks with desired uniform characteristics of a specific trait, such as fast growth, leaner meat, or higher milk production. Cloning is often pursued to produce animals that grow faster so they can be slaughtered sooner and to raise more animals in a smaller space.

For example, transgenic fish are engineered to grow larger at a faster rate and cows injected with genetically engineered products to increase their productivity. Another example of this is the use of the genetically engineered drug, bovine growth hormone (BGH or BST) to increase milk production in dairy cows. This has also been associated with increased cases of udder disease, spontaneous abortion, lameness, and shortened lifespan. The use of BGH is controversial; many countries (such as Canada, Japan, Australia, and countries in the EU) do not allow it, and many consumers try to avoid it. A rise in transgenic animals used for agriculture will only exacerbate current animal welfare and environmental concerns with existing intensive farming operations. (For more information on farming and animal welfare, visit the MSPCA’s Farm Animal Welfare page.)

Much remains unknown about the potential environmental impacts of widespread cloning of animals. The creation of genetically identical animals leads to concerns about limited agricultural animal gene pools. The effects of creating uniform herds of animals and the resulting loss of biodiversity, have significant implications for the environment and for the ability of cloned herds to withstand diseases. This could make an impact on the entire agriculture industry and human food chain.

These issues became especially concerning when, in 2008, the Federal Drug Administration not only approved the sale of meat from the offspring of cloned animals, but also did not require that it be labeled as such. There have been few published studies that examine the composition of milk, meat, or eggs from cloned animals or their progeny, including the safety of eating those products. The health problems associated with cloned animals, particularly those that appear healthy but have concealed illnesses or problems that appear unexpectedly later in life, could potentially pose risks to the safety of the food products derived from those animals.

Genetically Engineered Pets

Companion animals have also been cloned. The first cloned cat, CC, was created in 2001. CC’s creation marked the beginning of the pet cloning industry, in which pet owners could pay to “bank” DNA from their companion dogs and cats to be cloned in the future. In 2005, the first cloned dog was created; later, the first commercially cloned dog followed at a cost of $50,000. Many consumers assume that cloning will produce a carbon copy of their beloved pet, but this is not the case. Even though the animals are genetically identical, they often do not resemble each other physically or behaviorally.

To date, the pet cloning industry has not been largely successful. However, efforts to make cloning a successful commercial venture are still being put forth. RBio (formerly RNL Bio), a Korean biotechnology company, planned to create a research center that would produce 1,000 cloned dogs annually by 2013. However, RBio, considered a “black market cloner,” failed to make any significant strides in its cloning endeavors and seems to have been replaced by other companies, such as South Korean-based Sooam Biotech, now the world’s leader in commercial pet cloning. Since 2006, Sooam has cloned over 800 dogs, in addition to other animals, such as cattle and pigs, for breed preservation and medical research.

While South Korean animal cloning expands, the interest in companion animal cloning in the United States continues to remain low. In 2009, the American company BioArts ceased its dog cloning services and ended its partnership with Sooam, stating in a press release that cloning procedures were still underdeveloped and that the cloning market itself was weak and unethical. Companion animal cloning causes concern not only because of the welfare issues inherent in the cloning process, but also because of its potential to contribute to pet overpopulation problem in the US, as millions of animals in shelters wait for homes.

Cloning and Medical Research

Cloning is also used to produce copies of transgenic animals that have been created to mimic certain human diseases. The transgenic animals are created, then cloned, producing a supply of animals for biomedical testing.

A 1980 U.S. Supreme Court decision to permit the patenting of a microorganism that could digest crude oil had a great impact on animal welfare and genetic engineering. Until that time, the U.S. Patent Office had prohibited the patenting of living organisms. However, following the Supreme Court decision, the Patent Office interpreted this ruling to extend to the patenting of all higher life forms, paving the way for a tremendous explosion of corporate investment in genetic engineering research.

In 1988, the first animal patent was issued to Harvard University for the “Oncomouse,” a transgenic mouse genetically modified to be more prone to develop cancers mimicking human disease. Since then, millions of transgenic mice have been produced. Transgenic rats, rabbits, monkeys, fish, chickens, pigs, sheep, goats, cows, horses, cats, dogs, and other animals have also been created.

Both expected and unexpected results occur in the process of inserting new genetic material into an egg cell. Defective offspring can suffer from chromosomal abnormalities that can cause cancer, fatal bleeding disorders, inability to reproduce, early uterine death, lack of ability to nurse, and such diseases as arthritis, diabetes, liver disease, and kidney disease.

The production of transgenic animals is of concern because genetic engineering is often used to create animals with diseases that cause intense suffering. Among the diseases that can be produced in genetically engineered research mice are diabetes, cancer, cystic fibrosis, sickle-cell anemia, Huntington’s disease, Alzheimer’s disease, and a rare but severe neurological condition called Lesch-Nyhan syndrome that causes the sufferer to self-mutilate. Animals carrying the genes for these diseases can suffer for long periods of time, both in the laboratory and while they are kept “on the shelf” by laboratory animal suppliers.

Another reason for the production of transgenic animals is “pharming,” in which sheep and goats are modified to produce pharmaceuticals in their milk. In 2009, the first drug produced by genetically engineered animals was approved by the FDA. The drug ATryn, used to prevent fatal blood clots in humans, is derived from goats into which a segment of human DNA has been inserted, causing them to produce an anticoagulant protein in their milk. This marks the first time a drug has been manufactured from a herd of animals created specifically to produce a pharmaceutical.

A company has also manufactured a drug produced in the milk of transgenic rabbits to treat a dangerous tissue swelling caused by a human protein deficiency. Yet another pharmaceutical manufacturer, PharmAnthene, was funded by the US Department of Defense to develop genetically engineered goats whose milk produces proteins used in a drug to treat nerve gas poisoning. The FDA also approved a drug whose primary proteins are also found in the milk of genetically engineered goats, who are kept at a farm in Framingham, Massachusetts. Additionally, a herd of cattle was recently developed that produces milk containing proteins that help to treat human emphysema. These animals are essentially used as pharmaceutical-production machines to manufacture only those substances they were genetically modified to produce; they are not used as part of the normal food supply chain for items such as meat or milk.

The transfer of animal tissues from one species to another raises potentially serious health issues for animals and humans alike.

Some animals are also genetically modified to produce tissues and organs to be used for human transplant purposes (xenotransplantation). Much effort is being focused in this area as the demand for human organs for transplantation far exceeds the supply, with pigs the current focus of this research. While efforts to date have been hampered by a pig protein that can cause organ rejection by the recipient’s immune system, efforts are underway to develop genetically modified swine with a human protein that would mitigate the chance of organ rejection.

Little is known about the ways in which diseases can be spread from one species to another, raising concerns for both animals and people, and calling into question the safety of using transgenic pigs to supply organs for human transplant purposes. Scientists have identified various viruses common in the heart, spleen, and kidneys of pigs that could infect human cells. In addition, new research is shedding light on particles called prions that, along with viruses and bacteria, may transmit fatal diseases between animals and from animals to humans.

Acknowledging the potential for transmission of viruses from animals to humans, the National Institutes of Health, a part of the U.S. Department of Health and Human Services, issued a moratorium in 2015 on xenotransplantation until the risks are better understood, ceasing funding until more research has been carried out. With the science of genetic engineering, the possibilities are endless, but so too are the risks and concerns.

Genetic engineering research has broad ethical and moral ramifications with few established societal guidelines.

While biotechnology has been quietly revolutionizing the science for decades, public debate in the United Statesover the moral, ethical, and physical effects of this research has been insufficient. To quote Colorado State University Philosopher Bernard Rollin, “We cannot control technology if we do not understand it, and we cannot understand it without a careful discussion of the moral questions to which it gives rise.”

Research into non-animal methods of achieving some of the same goals looks promising.

Researchers in the U.S. and elsewhere have found ways to genetically engineer cereal grains to produce human proteins. One example of this, developed in the early 2000s, is a strain of rice that can produce a human protein used to treat cystic fibrosis. Wheat, corn, and barley may also be able to be used in similar ways – at dramatically lower financial and ethical costs than genetically engineering animals for this purpose.