Gene therapy consists of adding new genes to a person’s cells to replace missing or malfunctioning genes. Genes, units of hereditary information, exist on chromosomes that reside in the nuclei of cells. Chromosomes contain long chains of DNA made of repeating subunits called nucleotides. Thus, a single gene is a finite stretch of DNA with a specific sequence of nucleotides. These nucleotides contain instructions used to create a particular protein. If a gene malfunctions—meaning it has the wrong sequence of nucleotides—then its corresponding protein does not get made or gets made incorrectly. As we learned through Mendelian Genetics, biologists call this gene malfunction a mutation, and it can lead to a number of diseases, including cancer and sickle cell anemia. Gene therapy aims to restore or replace a malfunctioning gene, thereby repairing the cell’s ability to correctly create a protein (Harris, 2013).
Scientists use viruses in order to insert the correct version of a gene into a host cell. Although viruses do not have nuclei or other cellular structures, they have nucleic acid, either DNA or RNA. Because they have no cellular structures of their own, viruses must invade cells and make use of cell equipment and enzymes in order to reproduce. Viruses are useful in gene therapy because they can carry genetic information into cells. A piece of viral DNA can be replaced with the DNA of a human gene. After the virus infects a host cell, that cell would make copies of the introduced gene and follow the specific gene expression instructions to create the associated protein. This process works as long as scientists modify the virus to prevent it from causing either a disease or an immune response (Harris, 2013).
Because gene therapy involves making changes to people’s genetic makeup, it raises several social and ethical concerns. One of these concerns involves the distinction between therapy and enhancement. There is a general consensus that gene therapy should be used as therapy—meaning it should be used to treat disease, as opposed to enhancement, which involves turning non-disease traits into more desirable traits (Mauron). However, in the future, it may become possible to perform genetic enhancements on human beings. Scientists have already made such enhancements with animals. In the late 1990s, scientists genetically engineered mice to have increased muscle growth and strength. This breakthrough could lead to similar developments among human athletes and make gene doping possible. As yet, this form of doping would be difficult to detect. The possibility of human gene enhancement raises the question of whether improving one desirable trait could have negative consequences on other traits. It also raises the question of whether gene enhancement is ethical in the first place (Simmons, 2008).
Another implication of gene enhancement is the possibility to choose non-disease traits for embryos in vitro before the embryos are implanted into the womb. Such trait selection and enhancement raises moral issues for both individuals and society. First is the issue of safety—could there be harmful effects that would not exist otherwise? One reason safety is a concern is that most genes have more than one effect. For instance, in the late 1990s scientists modified a gene linked to memory in mice which, while improving the memory and learning of the mice, also had the effect of increasing their sensitivity to pain. Another moral concern is the issue of equity. Not everyone would be able to afford such expensive technology. If only the well-off have access to gene enhancement, it could create a new form of inequality and perhaps a new form of discrimination (Simmons, 2008).
Other social and ethical implications arise involving the distinction between somatic and germline gene therapy. So far research on human gene therapy has been conducted on somatic cells, cells that are not involved in reproduction. Therefore, somatic gene therapy affects only the individual being treated and not any of the individual’s descendants. In contrast, germline therapy is conducted on germ cells—eggs and sperm—that are involved in reproduction and can thus affect the patient’s descendants (Mauron).
Germline gene therapy raises important ethical questions. On the one hand, it is more efficient to use germline therapy to get rid of a genetic defect once and for all than to repeat somatic gene therapies on each successive generation. On the other hand, germline therapy is tantamount to an experiment on unconsenting individuals, as those in future generations affected by the therapy cannot consent to it. Other ethical issues arise at the possibility of germline therapy being conducted on human embryos. Those who consider human embryos to have all the moral significance and rights of a person will conclude that not only must human embryo experimentation be rejected, but so must germline therapy. Others who believe that it is only in the later stages of development that humans become ethically and legally protected subjects will not find human embryo experimentation objectionable and would not rule out germline therapy solely because it may involve human embryo experimentation. So far there is no consensus on the ethical and legal status of human embryos. Some countries permit human embryo experimentation, others ban it, and others still are undecided. The question of the ethical standing of the human embryo is significant not only for germline gene therapy but for a number of other medical procedures as well (Mauron).
I believe it is ethical to use gene therapy to treat disease. I do not, however, believe it would be ethical to use gene enhancement to alter non-disease traits, at least not yet. My main concern with gene enhancement is equity. There should be some inequality in society to act as an incentive for people to work harder to get a better life. But there should not be so much inequality that even the inequality of opportunity exists—working harder does not do much to get you a better life if you were not born under the right circumstances. There is already excessive inequality, as people do not have equal opportunity. Where you end up is largely a result of what family you are born into. Allowing gene enhancements would only exacerbate the situation. Equality of opportunity is a right that thus far has gone unrealized. It would be unethical to bring about circumstances that we know would further diminish that right.
With regard to germline therapy, it would be useful to use the golden rule: treat people the way you would like to be treated. In this case, if my parents or other ancestors used germline therapy that kept me from getting a serious disease, I would be glad they did. So by the golden rule standard, it is ethical to use germline gene therapy to treat diseases. What about germline gene enhancement? If my ancestors ended up changing my traits in the way I would want them to be changed, I would be happy they made those changes. But if they changed traits I would not want to be changed, I would not like that they made the changes. Since the traits that are considered desirable can be different from generation to generation and even from person to person within the same generation, it would not be ethical to use germline therapy for gene enhancements.
The golden rule is also useful with regard to the ethical standing of human embryos. If I were an embryo, I would not be able to think or feel. Consequently, I would not care what anybody did with me. I would not mind any experimentation done on me, so long as I would not be developing any further such that I would feel any negative effects from the experimentation. So by the golden rule standard, human embryos do not have the same moral significance and ethical standing as human beings in later stages of development.
Harris, W. (2013, August 19). How Gene Therapy Works. Retrieved from HowStuffWorks: http://www.howstuffworks.com/life/genetic/gene-therapy.htm
Mauron, A. (n.d.). Ethical Aspects of Gene Therapy. Retrieved from Geneva Foundation for Medical Education and Research: http://www.gfmer.ch/Endo/Lectures_09/ethical_aspects_of_gene_therapy.htm
Simmons, D. (2008). Genetic Inequality: Human Genetic Engineering. Retrieved from Genetic Inequality: Human Genetic Engineering: http://www.nature.com/scitable/topicpage/genetic-inequality-human-genetic-engineering-768