Arguments Against Inheritable Genetic Modification

1. IGM would lead to treating children and all people like objects. Germline technologies would contribute strongly to parental expectations of "pre-selecting" their children's traits, and to the cultural construction of human beings as biologically perfectible artifacts. This would change the nature of the parent-child relationship, and would likely have other profound and destabilizing socio-cultural impacts.

2. IGM is a eugenic technology that would almost certainly increase the social and economic disparities between privileged elites and the great majority of others. Germline manipulation would always be expensive, and real or perceived "enhancements" would thus accrue to the offspring of the affluent. Even proponents of IGM acknowledge that such practices could lead to the emergence of "genetic castes," and of social rifts so vast that any notion of a common humanity could be lost, with horrific consequences.

3. It is effectively irreversible. Unanticipated negative effects of IGM would be passed on to all future generations.

4. Inheritable genetic modification constitutes inherently unsafe human experimentation. It would be impossible to anticipate fully the effects of inserting genes into human cells.

Rebuttals to Arguments Against Inheritable Genetic Modification

1. Germline-engineered children need not be considered "objects" to any greater degree than are non-germline-engineered children.

2. Society can redress inequalities created by IGM by distributional transfers of resources after the fact, or can prevent inequalities by making IGM services available to all people.

3. We can aim to modify genes at the germline level in ways that block their transmission to the next generation.

4. All innovative efforts at medical progress entail some risk. Society can pledge to compensate anyone who suffers. Many problems that might be created as a result of germline modification could be corrected by using the same techniques that caused them.

Arguments in Favor of Inheritable Genetic Modification

1. Inheritable genetic modification can be used to allow couples to avoid passing on serious genetic diseases such as Tay-Sachs.

2. Inheritable genetic modification can allow a couple, both of whom are homozygous for a defective gene, to have a healthy child that is related to both of them.

3. Inheritable genetic modification can allow couples to "enhance" their children to be healthier, longer lived, more athletic, more intelligent, more attractive, and in general to have more of the qualities that all of us wish for our children.

4. Inheritable genetic modification will occur even if banned, because demand will be strong and people will be willing to pay. Rather than encourage black markets and likely abuses, we should legalize the practice so that it can be safely regulated.

Rebuttals to Arguments in Favor of Inheritable Genetic Modification

1. It is simply not true that IGM is needed to allow parents to avoid passing on serious genetic disease. Other means already exist to accomplish this same goal, in all but a vanishingly small number of cases. In the technique known as preimplantation genetic diagnosis, for example, couples at risk of passing on a gene-related disease use in vitro fertilization to conceive several zygotes, and only those found to be free of the harmful gene are implanted and brought to term. No manipulation of genes is required. Egg and sperm donation, and adoption, are also available. Germline manipulation is necessary only if you wish to "enhance" your children with genes they wouldn't be able to get from you or your partner.

2. Persons homozygous for genetic diseases who are able to marry and have children typically have a mild form of the disease, and thus their children are likely to have the mild form as well. In any event, the number of cases of the situation described is rare, and the merits of developing germline engineering for those very few cases does not warrant the incredible risks that this would entail for human society.

3. To embark on a trajectory of germline "enhancement" would change forever the nature of human life and society, would likely erode our sense of a common humanity, and would feed back upon itself in ways that we would be quite incapable of predicting. We can enhance our lives and those of our descendants in a myriad of ways, without running the risks that germline modification entails. Furthermore, parental rights are not absolute. They are always evaluated in relation to the well-being of children and of society.

4. To argue that IGM is inevitable, and therefore should be legalized, disregards historical experience and common sense. One might as well argue that because child abuse and murder occur, they should be made legal. Strong, effective laws, and public advocacy, can reduce or even eliminate black-market germline engineering.

Summary Comment

Although different people will judge one or another argument concerning inheritable genetic modification in different ways, the Center for Genetics and Society believes that when all the arguments are considered together the case for allowing it is not compelling, and that the potential harms of doing so are immense.

Last modified June 1, 2006