The recent announcement that a Massachusetts company’s cloning experiments could theoretically lead to a cloned human being has brought an increased urgency to the debate over the ethics of cloning. Cloning involves growing cells that contain the same genetic material as the donor cell, but without the combination of egg and sperm. To some people, cloning offers the promise of medical advances such as perfectly matched organs for transplantation. To others, cloning interferes with nature or God, and destroys human life in its most basic form.
Human beings and animals typically grow from conception when a sperm cell fertilizes an egg cell, thereby combining the parents’ DNA and genetic material. Cloning, on the other hand, is performed by transferring the DNA from the nucleus of one cell into an egg cell whose nuclear material has been removed. The modified egg cell has a full complement of DNA material from the donor cell without the need for fertilization by sperm. The egg cell is then stimulated to grow and divide.
The original donor cell is not a sperm or egg cell, but can come from any part of the body. The resulting being would have the same characteristics -- at least those controlled by DNA and genes -- as the donor individual. In essence, it would be possible to make a twin human being from any single body cell without the need for a traditional mother or father.
Medical Opportunities and Moral Concerns
There are two primary issues related to the ethics of cloning, according to Arthur R. Derse, MD, JD, Associate Clinical Professor of Bioethics at the Medical College of Wisconsin’s Center for the Study of Bioethics.
- Should we be working on cloning human beings?
- Is cloning human beings safe?
A national bioethics advisory commission on human cloning was established to study these issues. It has recommended at least a 5-year ban on human cloning until more information is available about safety issues in cloned animals.
The experiments by the Massachusetts company, Advanced Cell Technology, will have limited scientific impact, according to Dr. Derse. ACT’s cloned human cell multiplied into only six cells. Still, the company will likely attract more investors as a result of the publicity.
There have already been a limited number of parents who have decided to bear a child to provide matching bone marrow for an existing child with leukemia. In theory, cloning could allow perfectly-matched bone marrow cells to be grown from the healthy body cells of an ill child, or individuals requiring an organ transplant could have a perfectly-matched organ cloned from their own body cells. In those cases only the needed tissue would be cloned, not a complete human. Cloning a specific type of body tissue, however, is actually more difficult than cloning a complete human being. We do not yet understand the genetic instructions that determine what cells become which types of tissue.
Such opportunities are exciting for the medical community -- and for many people with intractable health issues -- because of the shortage of traditional donor tissue and the great risk that transplanted tissue from another person will be rejected by the patient’s body. But some individuals believe that such medical advances, even though still theoretical at this point, are ethically wrong. In addition, some people are concerned because the donor cell dies when the nuclear material is removed.
Cloning a complete human being raises additional concerns regarding ethics and safety. While parents who lose a child may want to clone a twin from the dead child’s cells, the cloned child may be quite different in personality than the first child. The environment in which the cloned child grows up in won’t be exactly the same. Furthermore, while the nuclear DNA of the children will be the same, genetic material existing in the egg cell outside the nucleus will also play a role in the development of any cloned individual. This makes the outcome of cloning a complete individual less predictable and more dangerous.
In Great Britain in 1997 a sheep named Dolly became the first cloned mammal; however, there were more than 250 failed attempts before Dolly was successfully cloned. Dolly has obesity problems that her “parent” did not have. This points out potential safety issues that could affect any cloned individual because the long-term biological results of cloning are simply unknown.
Stem Cell Research
Stem cells are “master” cells that carry all the chemical codes to become any type of human tissue, including organ, nerve, skin, muscle, blood or bone. Stem cells are usually derived from an embryo that was created after sperm fertilized an egg, although cloning can also be used to produce stem cells. The embryo is destroyed when the stem cells are removed. As an example of the work in this field, scientists believe it might one day be possible to create cells that secrete insulin. The cells could be implanted in diabetics to treat or cure diabetes.
Public opinion against cloning is much greater than against stem cell research, which is generally supported by the public, according to Dr. Derse. Theoretically, existing stem cells could be stimulated to reproduce additional stem cells. There are a limited number of stem cell lines available and no additional lines may be created at this time in the US because of federal regulations. The national bioethics advisory commission is currently discussing stem cell research, but has not made any recommendations. A presidential commission on the topic has also been formed. The US Department of Health and Human Services ruled in 1999 that a national ban on research in which human embryos are destroyed does not affect stem cell research if the embryos are already in existence.
