The Views of the United States on the Science and Ethical Implications of Human Cloning

Date: 02/26/2002

Distributed by the US Delegation to the United Nations Meeting on a Treaty to Ban Human Cloning, February 26, 2002


A. The United States’ Position

The United States supports a global and comprehensive ban on human cloning through somatic cell nuclear transfer, regardless of the purpose for which the human clone is produced. The United States believes that so-called “therapeutic” or “experimental” cloning, which involves the creation and destruction of human embryos, must be part of this global and comprehensive ban. Thus, the United States does not support a ban that is limited merely to “reproductive” cloning.

Any ban on human cloning should explicitly state that it does not prohibit the use of nuclear transfer or other cloning techniques to produce DNA molecules, organs, plants, tissues, cells other than human embryos, or animals other than humans.

In addition, we believe that nations should actively pursue the potential medical and scientific benefits of adult stem-cell research. Such research does not require the exploitation and destruction of nascent human life, nor does it open the door to the dehumanizing possibilities that will come with the cloning of human beings.

B. Scientific Background

Cloning refers to any process that results in the creation of an identical or nearly identical genetic copy of a DNA molecule, cell, or individual plant, animal, or human. Cloning occurs in nature. For example, identical twins are the product of a natural cloning event. There have also been recent scientific developments in cloning, such as the 1997 live birth of a sheep created using an experimental cloning method called “somatic cell nuclear transfer.”

Somatic cell nuclear transfer is a cloning technique used by scientists to produce a nearly genetically identical copy of an existing animal. The product of somatic cell nuclear transfer is an embryo. In simple terms, this embryo is created by replacing the nucleus of a female egg cell with genetic material from a “somatic” cell (which is a cell from the body other than a sperm or egg cell). There is no involvement of sperm. The resulting embryo is a clone that is nearly genetically identical to the donor of the somatic cell. (Since the donor egg also contains non-nuclear DNA in subcellular structures called mitochondria, the clone’s cells contain a very small amount of mitochondrial DNA from the donor egg cell. Thus, the clone is not exactly genetically identical to the somatic cell donor.)

Scientists conduct two types of experiments using somatic cell nuclear transfer. The first type of experiment, sometimes described as “reproductive” cloning, involves the creation of an embryo through cloning, and its subsequent implantation into the uterus with the objective of creating a living animal. Animal reproductive cloning experiments have very high failure rates (around 95%) and often result in stillbirths, spontaneous abortions, or offspring with severe congenital abnormalities.

The other kind of experiment, sometimes described as “research,” “experimental,” or “therapeutic” cloning, involves the creation of a cloned embryo, which is then used to derive stem cells or (after the embryo is grown to a fetal stage) tissues for transplantation. For example, after growth to the blastocyst stage (5-9 days), the embryo is destroyed in order to derive embryonic stem cells that hold the potential for the development for cell replacement therapies. (Stem cells are discussed more fully in the attachment.) Hypothetically, therapies based on stem cells derived from cloned human embryos would not be subject to immune rejection if transplanted into the human donor of the somatic cell used for cloning. Other kinds of research on cloned embryos have also been attempted. Recently, researchers have reported that they have grown cloned animal embryos in an animal host uterus beyond the blastocyst stage and successfully extracted differentiated tissue for replacement therapy.

Whatever its purpose, cloning through human somatic cell nuclear transfer necessarily involves the creation of a living human embryo. For this reason, the technique raises profound ethical and moral questions and is highly controversial.

There are other cloning techniques that do not raise these moral and ethical concerns. For example, scientists routinely employ cellular or molecular cloning in their work to make genetically identical cells for research. Although these other cloning techniques could be used to develop therapies to treat disease, scientists do not use the term “therapeutic” to describe these techniques. Rather, as discussed above, the term “therapeutic” cloning is used by scientists to describe cloning by somatic cell nuclear transfer for therapeutic, as opposed to reproductive, purposes. This latter type of cloning is also described as “experimental” cloning, or “cloning for research purposes.”

C. Ethical Implications of a Partial Ban Human Cloning

Human cloning for any purpose is an enormously troubling development in biotechnology. It is unethical in itself and dangerous as a precedent.

The possible creation of a human being through cloning raises many ethical concerns. It constitutes unethical experimentation on a child-to-be, subjecting him or her to enormous risks of bodily and developmental abnormalities. It threatens human individuality, deliberately saddling the clone with the genetic makeup of a person who has already lived. It risks making women’s bodies a commodity, with women being paid to undergo risky drug treatment so they will produce the many eggs that are needed for cloning. It is also a giant step toward a society in which life is created for convenience, human beings are grown for spare body parts, and children are engineered to fit eugenic specification.

We cannot allow human life to be devalued in this way. Some have proposed to prohibit only so-called “reproductive” cloning, by prohibiting the transfer of a cloned embryo into a woman to begin a pregnancy in the hopes of creating a human baby. This approach is unsound.

First, a ban that prohibited only “reproductive” cloning, but left “therapeutic” or “experimental” cloning unaddressed, would essentially authorize the creation and destruction of human embryos explicitly and solely for research and experimentation. It would turn nascent human life into a natural resource to be mined and exploited, eroding the sense of the worth and dignity of the individual. This prospect is repugnant to many people, including those who do not believe that the embryo is a “person.”

Second, to ban “reproductive” cloning effectively, all human cloning must be banned. Under a partial ban that permitted the creation of cloned embryos for research, human embryos would be widely cloned in laboratories and assisted-reproduction facilities. Once cloned embryos are available, it would be virtually impossible to control what was done with them. Stockpiles of embryonic clones could be produced, bought and sold without anyone knowing it. Implantation of cloned embryos, an easy procedure, would take place out of sight, and even elaborate and intrusive regulations and policing could not detect or prevent the initiation of a clonal pregnancy. Once begun, an illicit clonal pregnancy would be virtually impossible to detect. And if detected, governments would be unlikely to compel the pregnancy to be aborted or severely penalize the pregnant woman for allowing the implantation or for failure to abort the pregnancy. A ban only on “reproductive”cloning would therefore be a false ban, creating the illusion that such cloning had been prohibited.

Third, a ban that permits embryonic clones to be created and forbids them to be implanted in utero legally requires the destruction of nascent human life and criminalizes efforts to preserve and protect it once created, a morally abhorrent prospect.

Fourth, there may be other routes to solving the transplant rejection problem, and there is to date no animal research to support the claim that cloned embryonic stem cells are therapeutically efficacious. A legal ban on “therapeutic” cloning would allow time for the investigation of promising and less problematic research alternatives such as “adult” stem-cell research. It would also allow time for policy makers and the public to develop more informed judgments about cloning, and for the establishment of regulatory structures to oversee applications of cloning technology that society deems acceptable.

Attachment Stem Cell Overview

Cloned human embryos produced through somatic cell nuclear transfer are potentially a source of human embryonic stem cells. They could also be used for other experimental purposes. This attachment provides some information about embryonic and adult stem cells.

Stem cells are cells that occur in animals at all stages of development, from the embryo to the adult. They have different properties and abilities, depending on the age of the organism and the location of the stem cells within the organism.

Embryonic stem cells are derived from a 5-9 day-old embryo and are able to generate nearly all the cell types of the body. To date, human embryonic stem cell research has been conducted using stem cells derived from embryos that were created in the course of in vitro fertilization and were no longer needed for that purpose.

Adult stem cells occur in small numbers throughout the bodies of adult mammals. Under normal conditions, they generate the cell types of the tissue in which they reside. Under certain experimental conditions in the laboratory, or even after transplant into a living animal, adult stem cells may be able to differentiate into the specialized cells of several different tissues.

All stem cells are unspecialized (undifferentiated) they do not have any specific structures that allow them to perform specific functions such as carry oxygen or fire an electrical signal. Unlike specialized cells such as muscle cells, blood cells, or nerve cells, which divide slowly or not at all, stem cells are also capable of dividing and renewing themselves for long periods (self-renewing). Importantly, stem cells retain the unique ability to give rise to specialized cells (differentiation), such as muscle, skin, or neurons.

Scientists believe that human stem cells embryonic and adult, directed to differentiated to specific cell types offer the possibility of a renewable source of replacement cells and tissues to treat a myriad of diseases.