Human Cloning: Science, Ethics, and Moral Debate

What Is Cloning? Types and Scientific Processes

Cloning is the exact replication of a single gene or part of a single gene, achieved through specialized DNA technology. The result may be used for further scientific research or for whatever purpose the cloning was undertaken. The Human Genome Project, which conducts cloning experiments on a regular basis, refers to the entire process as "cloning DNA," and the copied DNA molecules are called "clone libraries." A second type of cloning makes use of the entirely natural process of cell division to produce numerous copies of a single cell. In this process, the genetic makeup of the cloned cell is an exact replica of the original cell from which the copies were made; this is referred to as a "cell line." The third type of cloning involves producing complete, genetically identical animals — one famous example being Dolly, the Scottish sheep that was successfully cloned. (Genome Glossary)

When Dolly was created in 1997, there was worldwide interest, concern, and considerable controversy, as might be expected. The very possibility that cloning could be applied to human beings raised serious questions, and the scientific and ethical considerations surrounding such a prospect became major issues commanding a great deal of attention. When the cloned sheep actually lived, it was hailed as the breakthrough of 1997 and raised numerous questions about what cloning is and how it can be done. The three types of cloning are recombinant DNA technology, reproductive cloning, and therapeutic cloning. Recombinant DNA cloning is also referred to as molecular cloning, DNA cloning, and gene cloning. (Cloning Fact Sheet)

The technical process of recombinant DNA cloning works as follows: a DNA fragment of interest is transferred from an organism to a self-replicating genetic element called a bacterial plasmid. The DNA can then be propagated in a foreign host cell, eventually creating a completely identical replica of the original cell. Generally, scientists studying a particular gene will use a bacterial plasmid to generate several copies of the same gene. Plasmids are self-replicating extra-chromosomal circular DNA molecules, distinct from the normal bacterial genome. When cloning a gene, the scientist first isolates the DNA fragment containing the gene of interest using restriction enzymes, and then joins it with a plasmid that has been treated with the same restriction enzymes. The fragment of chromosomal DNA then combines with its cloning vector in the laboratory, at which stage it is known as a recombinant DNA molecule. This is introduced into a suitable host cell, which in turn produces the recombinant DNA alongside its own host cell DNA. (Cloning Fact Sheet)

Plasmids can contain up to 20,000 base pairs of foreign DNA. The second type of cloning, reproductive cloning, is used to generate an animal with the same nuclear DNA as an existing animal — the method by which Dolly was produced. In this method, also known as somatic cell nuclear transfer (SCNT), the genetic material from the nucleus of a donor adult cell is transferred into an egg cell whose own nucleus — and therefore all of its genetic material — has been removed. The egg is then reconstructed using the donor material and treated with chemicals or electric current to stimulate cell division. An embryo forms and is transferred to the uterus of a female host, where it develops naturally until birth. This was the process that produced Dolly. What makes the process remarkable is the demonstrated fact that genetic material from a specialized adult cell can be reprogrammed to create an entirely new organism.

The third type of cloning, therapeutic cloning, is the process by which human embryos are used in scientific research. A common misunderstanding is that this process is intended to create another human being. In reality, therapeutic cloning is not aimed at creating a new person but at harvesting human stem cells so that the results can be used for scientific purposes — such as identifying the best methods to treat a particular disease or studying human development. Stem cells are of enormous importance to scientists and biomedical researchers because they are capable of regenerating virtually any type of specialized cell found in the human body. These stem cells are generally extracted after cell division has been occurring for approximately five days, at which stage the egg is known as a blastocyst. (Cloning Fact Sheet)

Therapeutic Cloning, Stem Cells, and Medical Promise

What is crucial at this stage is that at the moment of extraction, the embryo must die, and this is a matter of grave moral and ethical concern. Researchers, however, contend that once the technology of extracting stem cells is perfected, it may be possible to treat heart disease, cancer, Alzheimer's disease, and other currently incurable conditions. They also hope that stem cell extraction could be used to generate tissues and organs for transplantation — a remarkable possibility that would be foreclosed if stem cell extraction were banned. When an organ needs to be generated, DNA from the patient with the disease would be extracted and inserted into an enucleated egg, which then begins to divide. After sufficient division, the embryonic stem cells could be used for organ transplantation, because it is at this stage that they can be transformed into the patient's own tissue without the serious risk of organ rejection that causes so many transplantation failures.

This is because the cloned organ would match the genetic profile of the recipient. Cloning could therefore allow organs to be generated from cloned human embryos, potentially reducing and ultimately eliminating the need for organ donation. In November 2001, scientists from Advanced Cell Technologies (ACT) announced that they had produced a human embryo for therapeutic research purposes. Eggs were collected from women's ovaries with a minute needle, and a skin cell was inserted into each enucleated egg to serve as a new nucleus. A chemical called ionomycin was used to stimulate the egg to begin dividing, and cell division began, albeit with limited success. Of eight eggs used in the study, only three began to divide, and only one of those divided into six cells before stopping. (Cloning Fact Sheet)

Although cloning may have significant benefits and advantages, the question of whether it is truly moral to clone a human being or even an animal has generated intense debate with no clear resolution. It must be remembered that plant cloning has been practiced for many years, and it was only when animal cloning succeeded — in the form of Dolly — that the world took serious notice and began arguing that cloning life was not morally right. A university administrator commented that while the achievement was a great scientific breakthrough, he was uncertain whether research should continue, given the moral implications involved. (U community members debate morality of cloning)

Leonard Fleck, a professor of philosophy and medical ethics, stated that though the issue was sensitive and unsettling to most people, the genuine benefits of the technology must not be ignored. He argued that cloning technology was neither "evil," as some individuals claimed, nor morally wrong, as others insisted. Therefore, imposing restrictions or banning it would serve no good purpose beyond creating controversy. Taken in proper context, cloning technology could serve many important purposes. For example, if a couple both carry the gene for cystic fibrosis — a disease that fills the lungs and other organs with mucus — they face the risk of passing it to their offspring. However, if their offspring were produced through cloning, the risk of the child carrying cystic fibrosis could be reduced to a mere 25% chance, meaning the inherent risk could be substantially mitigated. (U community members debate morality of cloning)

The Moral and Ethical Debate Over Cloning

Professor Qiu Renzong, Director of the Program in Bioethics and Senior Research Fellow at the Institute of Philosophy at the Chinese Academy of Social Sciences, provided an early and influential treatment of cloning's history and its scientific and biomedical implications. He suggested that mankind could benefit greatly from this technology and stated that he saw nothing wrong with cloning human cells for research purposes. However, he also pointed out that cloning animals would be a different matter, because cloned animals could be prone to infections and diseases to which humans had never previously been exposed. Furthermore, he argued, it is not ethically or morally right to clone animals merely for the benefit of mankind, satisfying human needs at the expense of those animals. (Moral Implications of Cloning)

Professor Qiu outlined five basic moral principles to serve as an ethical yardstick for measuring any cloning procedure: non-malfeasance, beneficence, respect, justice, and mutual help. He stated that if these principles were followed, the various techniques of cloning could be made harmless to both humans and animals. Patients must be kept well informed about the techniques they would undergo. All individuals wishing to benefit from cloning must be treated impartially, regardless of age, sex, social status, or race. Special care must be given to socially vulnerable groups, such as the physically disabled and the elderly.

Cloning would be especially beneficial, Professor Qiu noted, for infertile people incapable of reproducing naturally. It could also help avoid certain genetic and hereditary diseases that are passed from parent to child through natural reproduction. Additionally, cloning could help scientists better understand human development. Cloned human beings could also serve as organ donors. Another potential advantage, he noted, is that cloning could provide options for homosexual couples who wish to have children. He also speculated that cloned human beings could potentially be engineered for extended longevity — long enough, he suggested, to crew spacecraft on long-range research missions. (Moral Implications of Cloning)

Against these advantages, Professor Qiu argued that since children are essentially "gifts from God," no human being has the right to interfere with nature's own reproductive process through human-developed technology. Cloning therefore conflicts with the moral tenets of religion and religious belief and should not be used to aid human reproduction. Most people regard life as precious and sacred, meaning that interference with the creation of life would not be widely tolerated. More importantly, cloning would inevitably reduce the diversity of the human gene pool and could destroy the integrity and stability of the family system. Finally, cloning raises significant legal complications. In conclusion, Professor Qiu stated that while cloning would be of great advantage to some, it is not morally or ethically right to clone and produce another human being, and it is best avoided where possible. (Moral Implications of Cloning)