Introduction
As a result of recent scientific advances, more is becoming known about the role of genetic traits in causing, allowing, and preventing human disorders and diseases. Through genetic testing of large segments of the population or specific individuals requesting it, scientists can identify those whose genes predispose them or their children to certain diseases or disorders. In some cases this knowledge may allow a person to undergo treatment, in others it may cause a person to refrain from having children. Unfortunately, though, no cure is currently possible for the majority of conditions discovered through genetic testing.
The practice of genetic testing and screening has created moral controversies about who should be tested and what should be done with the results.
Genes and Mutation
“Heredity” is the mechanism for the passing of physical traits from parents to their children and it works through small entities in the nucleus of each cell: chromosomes and their component genes and the chemical “DNA.” Half that genetic material comes from the mother and half from the father.
Genes may be affected by radiation, chemicals, and other factors and then mutate; a mutation is a change in the chemical sequence in the genetic makeup of the cell. If the genes in reproductive cells (sperm cells and egg cells) mutate, this mutation will be passed on to the child. Fortunately only a small percentage of mutations cause a disorder or disease.
Particular characteristics of an individual’s genetic structure can be learned by taking a genetic sample from some of the person’s cells. In this way it is possible to test for certain genetic characteristics that might result in health problems.
Types and Purposes of Genetic Testing
Genetic testing examines chromosomes and the content and sequences of DNA or related compounds (RNA, and other proteins and enzymes affected by genes) for particular variations that cause or predispose people to a disorder or disease. Testing can be considered to be diagnostic, predictive, or reproductive.
Individuals experiencing specific symptoms of a genetic disorder or disease can undergo diagnostic testing to see if they have it. Individuals without symptoms can undergo predictive testing (presymptomatic testing) to determine whether they are carrying a genetic variation that might cause future health problems. Reproductive testing determines whether individuals are carriers for certain genes that could be passed on to children and possibly cause a genetic disorder or disease. The genetic testing of embryos and fetuses is often considered to be predictive testing, but it is instead sometimes considered reproductive testing.
Some diseases or disorders are strongly linked to genetics. Tay Sachs disease and cystic fibrosis are caused by a single gene mutation, while Down syndrome is caused by an extra 21st chromosome. Others are influenced by genetics only in combination with certain environmental factors. Specific genetic variations, possibly among large numbers of genes, may make particular people more susceptible to cancer and heart disease but the genes alone probably do not cause these diseases.
Some genetically-linked diseases are more common within particular races or ethnic groups, for example, sickle-cell anemia among African-Americans and Tay-Sachs among Ashkenazi Jews.
Genetic testing among large groups of people is called genetic screening. In the U.S., newborns are routinely screened for indicators of certain disorders so they can receive early treatment if needed.
A number of questions arise about whether or not certain kinds of genetic testing should be done.
- Should couples who might pass along a genetic disorder to children be tested to decide whether or note to have such children?
- Should an embryo be tested in order for the parents to decide whether or not to have an abortion?
- Should people be tested for genes for a future disorder if there is no cure available for the disorder?
Reproductive Genetic Testing Prior to Conception
One or both parents may be aware of an unusually high number of ancestors or family-members with a genetically linked disease and decide to undergo reproductive genetic testing, prior to conceiving children, to determine the likelihood of passing the disease or disorder on to their children.
By testing one or both parents, unfortunately often only a probability, not a certainty, can be established of a child developing the disorder. In the case of some diseases, a child must get genes from both patients, while for others, the child need only get a gene from one parent. For some diseases a parent might carry the gene without having the disease, and then the parent may or may not pass on the gene. So the end result of genetic testing might be only a statement of the probability of a child having the disease or being a carrier for the disease.
One controversy in genetic testing is about decisions made based on such probabilities. At what probability should parents decide not to have a child? If the disease or disorder is tragic and severe, with no cure and no effective treatment, do parents have an obligation to refrain from having children if the probably is high? Should they forego having children if the probability is 75% but not if the probability is 25%? Can they be criticized if they go ahead and have a child if the probability is 75%?
Some people think we shouldn’t try to design babies to have or lack certain genetic traits, so on this view the whole idea of such testing is abhorrent. One also wonders what is implied about people afflicted with a disorder if one holds that one should not have children if there is a certain likelihood of a child having that disorder -- that those existing people should not have been conceived?
Those wishing to undergo such testing would argue that they have no moral obligation to have children at all. Making a decision based on the possibility of a significant disorder is not like trying to pick the genes for blue eye color. A child with a major genetic disorder may live a life of significant impairment, pain, and suffering. If there were a cure for such a disease, we would want to administer it. Absent such a cure, wouldn’t we want to prevent the disease in the first place?
Predictive/Reproductive Genetic Testing Used in the Decision to Abort
Predictive genetic testing is the testing of individuals to determine future susceptibility to a disease based on a current genetic makeup. In other words, a person who feels no symptoms of the disease undergoes genetic testing to see whether they are carrying the genes which may cause them to have the disease later.
This type of testing might be done on an embryo or fetus. If done prior to embryo implantation it can be called “preimplantation” testing or diagnosis. Preimplantation testing could only occur when the early embryo is available outside the womb for testing in the context of in vitro fertilization (IVF) efforts. If done on the embryo or fetus at a later stage it could be called “prenatal” testing or diagnosis. It is sometimes considered a type of reproductive testing, though an obvious difference with other reproductive testing is that is not being done on a parent prior to conception of the child, it is being done on the entity whose genes are in question.
This sort of testing on embryos and fetuses raises a controversy about termination of the embryo or fetus if the genes are undesirable, questions about health risk to the mother incurred by testing the embryo or fetus in the womb, and qualms about the practice of selecting a child based on genes. These issues are discussed below.
For the embryo to be obtained prior to implantation, through an IVF procedure, one of the cells would be removed for testing when the embryo was eight cells in size. This does not harm the embryo. The fate of the embryo depends on the outcome of test. If the embryo is normal it can be implanted into the womb and carried to term. If the embryo has a genetic disorder it can be discarded (and will die). Of course part of the controversy is due to the fact that such killing of embryos is considered by some ethicists to be morally impermissible.
If the embryo is to be tested after implantation (prenatal testing), a procedure such as amniocentesis or chorionic villi sampling would be used to obtain a tissue sample from the embryo or fetus. If the embryo or fetus has a genetic disorder it can be aborted (induced, elective abortion). Of course, abortion is itself morally controversial.
The procedure to obtain the tissue sample from the fetus represents a risk to the mother of complications and a risk to the fetus of spontaneous abortion or miscarriage. It is controversial whether this risk should be incurred by such a procedure.
In addition some will object to the whole idea of searching through embryos to find a genetically normal one to keep because it smacks of the idea of designer babies, which those critics find disturbing. The question that needs to be answered is whether there is a morally relevant difference between searching through embryos for one with a desirable trait such as blue eyes and searching for one free from genetic disorder. If there is a significant difference, one might object to the concept of designer babies (going for blue eyes, for example) and yet agree with the idea of trying to ensure one’s child does not suffer from a genetic disorder.
Predictive Genetic Testing When There is No Prevention or Cure
As already mentioned, predictive genetic testing is used to determine whether an individual is carrying a genetic disorder when the person does not currently show symptoms of the disease or disorder. Carrying specific genes may indicate the possibility of developing symptoms later. This type of testing is most commonly done if there is a family history of the genetically-linked disease.
Unfortunately this type of testing does not always produce certainty. Sometimes it can predict whether the individual definitely will or will not get the disease, though even then it is not always possible to tell the individual when symptoms will appear. At other times results may show only that there is a probability of getting the disease.
A further sobering thought is that few genetically-linked disorders and diseases that can be discovered through testing can be cured or prevented. If prevention is possible, early detection is important and fruitful. But if there is no prevention and no cure, controversy surrounds whether one would or should want to know that one has the genetic makeup that will inevitably or probably lead to the disease. For example, Huntington’s disease causes progressive deterioration of the brain cells and a resulting loss of control over movement and the ability to think. The disease strikes in adulthood and increasing deterioration cannot be prevented. If a child or young adult has the genetic makeup that will likely result in Huntington’s, would he or she want to be tested and find out?
In order to determine whether it is better to know or not know, some thinkers have tried to systematically consider all the possibilities of knowing or not knowing and having or not having a genetic disorder. If one knows one will likely get the disease, one may have the time and focus to get affairs in order, reprioritize life, and make more informed plans and decisions about marriage, family, and career. On the other hand such knowledge may bring anxiety, panic, anguish, and anger to the point of interfering with life. If one knows one will not get the disease, one can get on with life, make plans, and feel relieved.
If one is not tested one will never know, until symptoms appear, if they in fact ever do. One might be spared the emotional and mental issues accompanying a positive test, but counterbalancing that might be the anxiety of living with uncertainty.
A decision to get tested may involve others, such as family. Knowing either way may result in plans and actions that affect the lives of other family members. Does a spouse have a right to know? If results are learned before an impending marriage, is there a moral obligation to inform a future spouse before the wedding? And if one is tested the question will arise about family members, such as siblings and children, getting tested. Family members finding out they will not get the disease may feel happy but someone who learns they will not get the disease may feel guilt if siblings learn they will get the disease. Those finding out they will get the disease may feel anger and resentment that affect family relations.
Mandatory Prenatal Screening: Public Health or Eugenics?
Genetic screening is predictive genetic testing on a large scale or routine basis, as in, for example, widespread mandatory PKU (phenylketonuria) testing of infants. PKU is an inability to break down the amino acid phenylalanine; undetected and untreated the condition can lead to brain damage. Supporters of such tests argue that testing helps affected individuals and the state. Detected early enough, PKU can be treated through diet, thus benefitting the individual and saving the state the possible cost of caring for individuals who would be mentally impaired if not caught. Critics charge the cost-benefit issue is more complicated than portrayed (who pays for the test, who does or should bear the cost of caring for impaired individuals, how many would be impaired if screening were voluntary rather than mandated, etc.) and they also claim it involves the issues of personal freedom and parental rights to make their own decisions about healthcare for their children.
Even more controversial would be public screening programs for genetic diseases for which there is no cure or effective treatment. Public health officials would argue that society has a legitimate interest in learning of individuals with genetic disorders. But critics would argue that people with genetic disorders and their parents have a moral right to make their own decisions about detection and treatment. In a situation in which there is no cure, forcing a child to live with the knowledge that he or she has a genetic disorder can be seen as cruel.
Critics also wonder if such public screening is really done for the public good or more a legacy of eugenics programs of the past. Negative eugenics is the attempt to preserve the public gene pool by discouraging or prohibiting procreation among those with genetic disorders. In the past, many countries (including the U.S.) routinely sterilized certain “undesirable” people. It was claimed, for instance, that mentally retarded people did not have the capacity to raise children and so the public had an interest in preventing them from reproducing. The worry is that widespread genetic screening could be used for similar discriminatory purposes against individuals.
Discrimination Based on Genetic Information
Another area of concern is the possibility of discrimination against individuals for health or life insurance, or employment, based on information about them discovered through genetic testing. Health information is normally considered confidential between healthcare providers and patients, though other parties such as insurance companies and even employers may obtain some of an individual’s health information in the course of processing payments and insurance and job applications. But sometimes insurance companies and employers learn of protected health information they have no right to know.
On the one hand, an employer may have an interest in certain types of genetic tests for employees if the employees with particular genetic traits would likely be harmed by workplace exposure to certain conditions. If the employee has a genetic predisposition to some type of cancer, for instance, the employer might argue that to protect that employee it should screen such an individual to exclude him or her from certain chemicals or radiation that might result in such cancer.
Likewise, an insurance company might argue that they commonly ask for health information on the application so that the individual can be placed in the proper risk group, otherwise healthy individuals without risky conditions wind up underwriting the cost of insurance for risky individuals. This is a commonly accepted practice in life insurance underwriting, for instance. The company might argue that health-related genetic information is similar and they should be allowed to learn of it before issuing policies.
Critics contend that employers will likely use genetic information not only to protect workers but also to exclude risky applicants from being hired and costing the company money in health insurance premiums. As well, the charge is that health insurance or life insurance companies will raise premiums for individuals with a certain genetic makeup when there is no absolutely certain connection between those genes and diseases or predictability that such an individual will get the disease. Individuals with certain genetic conditions may experience discrimination in employment and insurance and might be unable to obtain jobs or obtain insurance at affordable rates.
The U.S. Congress, responding to such fears, recently passed the Genetic Information Non-Discrimination Act, making it illegal to discriminate against a person in employment or health insurance coverage based on genetic information. In spite of this some believe the danger of discrimination is still present.
