Genetics and Human Behavior: II. Philosophical and Ethical Issues
II. PHILOSOPHICAL AND ETHICAL ISSUES
Behavioral genetics has been a focus of intense controversy both within and outside the field almost from its inception.
Much of the controversy within the field involves conceptual and methodological issues such as the question: Do twin studies yield the most scientifically reliable conclusions about the degree to which genes shape behavior? Rather than address those issues, this entry examines some of the social and ethical issues that may arise as a result of what researchers in behavioral genetics claim to know regarding the role of genes in shaping human behavior. Special attention is given to what may be referred to as the promise or the threat of eugenics, depending on one's philosophic perspective, as that relates to developments in the field.
Eugenics is characterized by the devising of interventions aimed at improving the quality of the human genome. Those interventions can be either social behavioral or molecular. In The Republic Plato recommended using the power of the state to arrange marriages of the best with the best. A practical problem with that approach is that it is a very crude and haphazard way to improve the human genome. Philosophical and scientific thinking for roughly the next 2,000 years was locked into Platonic and Aristotelian premises, specifically the belief that the nature or essence of each living thing is eternal and immutable. However, the emergence of evolutionary theory from the work of Charles Darwin radically undermined that premise.
The immutable natures of all plants and animals in fact have been changing constantly (or perishing) in response to environmental forces over millions of years. In the nineteenth century emerging agricultural sciences showed was that such change need not be left to slow and chaotic natural forces; instead, the tools of science could be used to effect deliberately changes that suited various human needs. Darwin's cousin Sir Francis Galton took the next logical step and suggested that deliberate reproductive control could be applied to human beings as well. In 1883 he started using the term eugenics to describe those efforts.
In the early part of the twentieth century the eugenics movement was endorsed by many prominent scientists, intellectuals, and political leaders (Kevles), including Charles Eliot, the president of Harvard University. Still, the tools available for eugenic purposes remained crude and ethically problematic. It is one thing, morally speaking, to create social practices that would encourage the marriage of the best with the best; it is quite another to use the coercive powers of the state to sterilize individuals who are judged unfit to reproduce "their kind."
In the early twentieth century enthusiasm for eugenics might be said to have reached a peak in 1927 with the U.S. Supreme Court decision Buck v. Bell. Oliver Wendell Holmes there upheld the constitutionality of state sterilization laws with the ringing words "Three generations of imbeciles is enough!" The rise of Nazism and the appropriation by the Nazis of the rhetoric of eugenics to justify their atrocities resulted in a tarnishing of the eugenics movement in the middle part of the century. To this day those unsavory connotations remain attached to the term eugenics.
The second half of the twentieth century saw the discovery of the DNA molecule by Francis Crick and James Watson, followed by the very rapid development of genetics as a science and the dissemination of genetic insights and techniques into other areas of science, such as behavioral genetics in psychology. That effort culminated in the mapping of the entire human genome, beginning in the 1990s to April 2003. One consequence of those scientific successes is that eugenics has regained a considerable degree of scientific and moral legitimacy.
A primary reason for the renewed legitimacy is the fact that molecular biology offers the promise of tools that can achieve with great precision whatever eugenic goals we might embrace. Furthermore, the emphasis by advocates of the new eugenics is on the voluntary use of those tools by individuals as opposed to their forcible imposition by the state. In addition, the emphasis of advocates for eugenics is not on improving the quality of the human genome. Instead, that emphasis is individually therapeutic, as in traditional medicine. The dominant goal is to improve the lifetime welfare of future possible children who otherwise would be faced with genetic deficiencies that would compromise the length and quality of their lives. However, there are critics of all forms of eugenics, whether new or old, whether aimed at eliminating debilitating medical conditions or enhancing desirable human traits such as intelligence (Rifkin; Kass).
Eugenics: Some Broad Moral and Political Issues
Who should be the we that would have the moral authority to determine eugenic goals? Should this be part of the authority and responsibility of the state, or should such decisions be left to autonomous individuals? If people chose to invest that authority in a liberal democratic state, would careful adherence to legitimate democratic processes be sufficient to guarantee the moral legitimacy of the eugenic policies that emerged from those processes? If conscientious adherence to such democratic processes were insufficient, what extrapolitical norms could justifiably be invoked for purposes of assessing those processes and policies critically? What would be the source of the moral authority of those norms?
Alternatively, if the coercive powers of the state were judged to be problematic, especially with regard to intimate and personal matters such as the genetic endowment of children, eugenic goals could be left to the choices of individuals and the private organizations that would provide the means necessary for achieving those goals, such as genetic testing and alternative means of reproduction. This would be what Philip Kitcher refers to critically as "laissez faire eugenics." If such eugenic outcomes were both privatized and uncoerced, would that guarantee the moral and political legitimacy of those outcomes? Troy Duster thinks not. Or would a state be correctly judged to be irresponsible for allowing any and all voluntary eugenic decisions to happen in an entirely unregulated fashion primarily because the best interests of future children would be at risk?
These questions are raised in the context of a liberal, pluralistic, secular, tolerant democratic state that seeks to maximize the scope of individual liberty as long as that liberty is not used to threaten the equally valuable rights and liberties of others or undermine important public interests. This type of state recognizes that there are many reasonable visions of what it means to live a good life and that consequently a state must refrain from using its coercive powers to impose a preferred vision of a good life on those who would not choose it for themselves (Rawls). It is a state that will not allow sectarian religious preferences to shape public policy, especially if a policy is needed to guide intimate life decisions. Thus, critical religious appeals to the language of "playing God" will have little legitimacy as rational support for public policies that might be aimed at outlawing "private eugenic efforts" by parents to shape the genetic endowment of their children (Peters; Evans).
Eugenics: Some Policy Issues
A state that did nothing to regulate any of the medical technologies that might be used to shape or choose the genetic endowment of future children might be regarded as irresponsible. After all, one version of the argument might go, how can a compassionate and responsible society allow children to be born with serious medical disorders, such as cystic fibrosis or Tay-Sachs disease, that would very adversely affect the length and quality of their lives when that society has the technology to prevent such harm? Alternatively, how can a compassionate and responsible society allow genetic and medical researchers to experiment with alterations in the genetic endowments of embryos if there is any risk of significant harm to the children who eventually would be born?
Both of these questions suggest a necessary and legitimate role for the state in regulating the development and use of technologies that have a eugenic purpose. However, that leaves unspecified the norms that justifiably could be invoked in a liberal pluralistic society for purposes of shaping both the content and the purpose of those policies. For example, should a compassionate and responsible society use tax monies to underwrite basic research aimed at providing the capacity to shape the genetic endowment of future children? This society already spends billions of public dollars each year through the National Institutes of Health to address an enormous range of human health problems, many of which have genetic roots. Alternatively, the genetic research that people imagine necessarily would involve the destruction of numerous embryos that were only a few days old. That would violate the deep moral convictions of many people in the society who are concerned about protecting all human life from the moment of conception. Are their concerns sufficient to take such public funding off the table?
If the destruction of embryos is a legitimate societal concern, less offensive policy options are available for achieving eugenic goals. There could be public funding for eugenic education. This could take many forms, but the general idea is that future parents would know what options were available to them for shaping naturally or technologically the genetic endowment of their children. A society could encourage widespread and complex genetic testing long before marriage by underwriting the cost of that testing so that individuals would be motivated to refrain from having children altogether, refrain from having children with partners who were genetic mismatches, or refrain from reproducing except through the use of an alternative reproductive technology.
The policy options cited above would come under the rubric of utopian eugenics, a phrase introduced by Philip Kitcher. That phrase is intended to suggest the desirability of a society pursuing a range of eugenic goals within the constraints of a liberal pluralistic political framework. Broad public genetic education and public support for access to genetic testing would increase the capacity of individuals to make autonomous eugenic choices regarding their own children in the light of their deepest values. Such public support also would demonstrate responsible but noncoercive regard for the wellbeing of future children who otherwise would be vulnerable to the profoundly harmful vagaries of the genetic lottery.
The word harm merits special emphasis in understanding the thrust of utopian eugenics. Kitcher and others are morally and politically comfortable with eugenic policies aimed at giving parents tools for preventing substantial genetic harm to their future children. However, many people (Parens) are less comfortable with eugenic interventions aimed at enhancing the genetic endowment of future children. This raises two questions, one moral and the other conceptual: Is there a significant moral difference between genetic interventions aimed at minimizing genetic harm and genetic interventions aimed at enhancing traits? Can a sharp conceptual distinction be drawn between what are called genetic harms and what are called genetic enhancements? These questions are discussed and analyzed thoroughly, along with their practical implications, by Allen Buchanan and coauthors.
Behavioral Genetics and Eugenics: Distinctive Moral Concerns
The questions raised above might be characterized as generic questions about eugenics. The examples used have all been about physical diseases with strong genetic links. However, the actual history of the eugenics movement has largely involved what today would be labeled behavioral genetics. That is, what those advocates wanted eliminated from the human gene pool were genes associated with being feeble-minded, lazy, alcoholic, violent, inclined to criminality, and so on. This raises a host of other moral and political and philosophic issues that are much more perplexing than the issues listed above.
If an individual has a gene variant that will result in affliction with cystic fibrosis or Huntington's disease or an early-onset form of Alzheimer's disease, such disease processes are seen to be accidental afflictions of that individual's body. Those diseases do not alter people's fundamental nature as persons, as rational moral agents. However, if an individual is feeble-minded (or a genius), alcoholic, or inclined to criminality as a result of his or her genetic endowment, this seems to be integral to his or her nature as a person, as a choice-making creature. It also raises the troubling question of whether individuals with such genetic endowments can be held accountable for the behaviors that seem to flow from those endowments. The argument, stated very crudely, would be that people do not hold individuals responsible for having cystic fibrosis; consequently, those individuals should not be held responsible for their criminal behavior if that behavior is just another product of their genetic endowment.
Other troubling social consequences may be associated with behavioral genetics. Genes seem to "travel" in clusters: Family resemblances are a common social phenomenon. Those resemblances also show up among members of ethnic and racial groups. None of these observations are intrinsically troubling. However, if a particular racial or ethnic group is perceived socially to have many members who are less intelligent, more violent, more prone to engage in criminal activity, and so on, and if those undesirable traits are believed to be genetically rooted, those social groups as a whole will be vulnerable to serious social stigmatization.
The practical argument is obvious: If members of that group cannot benefit from social investments in education, why waste resources on them. In this way the worst social prejudices can be given scientific and political legitimacy as well as insulation from moral criticism. That is, if individuals in the disfavored group are denied various social opportunities, those denials can be justified morally on the grounds that those individuals are genetically incapable of taking advantage of those opportunities. This issue has been the focus of a political firestorm that initially was generated by Arthur Jensen and then reignited by Charles Murray and Richard Herrnstein.
Behavioral Genetics: Key Elements of the Science
Moral judgments about personal responsibility for behavior or social discrimination must take into account relevant well-established scientific facts. Thus, it would be morally wrong to hold an individual who is completely in the grip of psychotic delusions responsible for his or her behavior in the same way one does with a person with normal rational capacities and moral sensibilities. At least two popular beliefs associated with genetics represent a gross distortion of the actual science and an equally gross distortion of related moral judgments.
The first belief is that people's fate is in their genes, that the genetic endowment of an individual is a future diary of that individual. In other words, people's behavior is at least very strongly determined by their genes. The second belief is that for any biological fact about people there is a gene for that biological fact. Thus, if scientists look hard enough, they eventually will find a gene for depression, a high IQ, aggression, criminality, being gay, and so on. A headline from Time magazine (Lemonick) is illustrative: "The Search for a Murder Gene."
What is referred to colloquially as the Huntington's gene would reinforce both of these popular misconceptions. That is, if an individual has inherited this gene, it is almost 100 percent certain that that person will have the disease (although there is considerable variation in the age at onset and the intensity of the disorder). That person is fated in a very strong sense. No personal behavior and no environ-mental variables can alter that fate. However, this picture of genetic determinism seems to have an extremely limited range of application. No human behavior of even minimal complexity seems to be genetically controlled in that simple a fashion (Ehrlich and Feldman; Beckwith and Alper; Ridley; Schaffner).
This entry does not address the philosophic issues and arguments associated with the free will–determinism debate or the debates in the philosophy of mind about whether mental events are nothing more than mechanistic brain states. However, a review of core scientific propositions that would be endorsed by a wide range of behavioral geneticists and a linking of those propositions with core scientific propositions in the neurocognitive sciences probably would provide a better basis for identifying and addressing related moral and political issues such as the question of the possibility of moral responsibility.
The Nature of Human Nature
Steven Pinker is the author of a provocative book titled The Blank Slate: The Modern Denial of Human Nature. There are three "myths" he intended to undermine in that book: (1) the belief that human beings are born as blank slates (from the philosopher John Locke) that are shaped completely by experience, (2) the belief in the ghost in the machine (from the philosopher Renée Descartes), which holds that the mind is a nonphysical entity that is connected mysteriously to people's physical bodies, and (3) the belief (from the philosopher Jean-Jacques Rousseau) that human beings are born as "noble savages," that they are born morally innocent and corrupted later by social institutions. Pinker contends that none of these beliefs can be supported by contemporary science.
Pinker argues that human beings have a nature at birth, that what is referred to as the mind is really the human brain, that the architecture of the brain is the product of eons of evolutionary development, that very complex interactions among many genes (as well as complex environmental factors) are ultimately responsible for that brain architecture, and that the detailed architecture of the brain varies from one individual to another as a result of the genetic variation and environmental influences that distinguish individuals. This genetic variation among individuals includes both cognitive and emotional differences.
Pinker is comfortable with the idea that from birth some individuals are more shy or more outgoing than others, more happy or more depressed, more inclined to be socially conformist or to engage in antisocial behavior, more inclined to be forgiving or to erupt in anger, and so on. For Pinker the same thing is true with respect to the display of intellectual abilities. He sees all these behavioral predispositions as ultimately being rooted in the genetic endowment of each individual; this is why he rejects the notion that humans at birth are noble savages or blank slates.
Some people consider the picture Pinker has painted excessively deterministic and mechanistic, both eviscerating any basis for moral responsibility for human behavior and reinforcing deep social prejudices against certain racial and ethnic groups. However, that conclusion is not warranted. What Pinker writes (p. 48) and what generally would be endorsed by behavioral geneticists is the following: "Most psychological traits are the product of many genes with small effects that are modulated by the presence of other genes, rather than the product of a single gene with a large effect that shows up come what may." He goes on to note that the effects of most genes are probabilistic and that the environment often modulates the effects of particular genes in complex ways. This is why identical twins do not live identical lives.
Behavioral Genetics and Eugenics: Contemporary Ethical Concerns
In 2002 in Great Britain the Nuffield Council on Bioethics addressed these issues and reached essentially the same conclusions. That is, the council sees no reason why research in behavioral genetics necessarily yields a fatalistic picture of human life in general or an undermining of the human capacity for moral judgment and moral responsibility. The genetic endowment of individuals establishes a range of behavioral options and predispositions related to personality, but the precise way in which those predispositions manifest themselves in a particular individual is a complex product of environmental chance and the deliberative capacities of that individual.
Those deliberative capacities can be influenced for better or worse by the formal and informal social learning opportunities offered in particular social contexts. For example, an individual may have a genetic endowment that predisposes him or her to react depressively to a range of disappointments and frustrations. However, an individual who is reflectively aware of those behavioral predispositions as a result of diligent parenting, sensitive friends, or personal reading may adopt a range of psychological and behavioral strategies that minimize the potentially damaging results of those depressive feelings. Alternatively, that reflective awareness might suggest taking medications aimed at altering the brain chemistry that sustains those feelings of depression. In either case what is illustrated is a responsible reaction to what might be described as innate features of one's personality. Kay Jamison's struggle with depression, as recounted in An Unquiet Mind (1995), is illustrative of these points.
If the picture sketched here is roughly correct and if the work of behavioral geneticists does not undermine people's capacity to be responsible moral agents, are any other moral issues raised by this research? The work of the Nuffield Council (2002) is helpful in responding to this question. The council points to two large concerns that potentially raise moral issues: medicalization and eugenics.
The term medicalization typically is used to express a specific criticism: that what once was regarded as a normal behavior or bodily state now is regarded as abnormal because there are medical interventions that give people control over that behavior or state. Some people are just shy. This is a fact about some individuals that is accepted routinely. However, if antidepressants such as Paxil can alleviate such behavioral dispositions and allow individuals to be more sociable (per social expectations), such individuals may no longer be accepted as shy persons. Instead, they may be diagnosed as shy and advised (expected) to seek appropriate medical help.
There is no simple response to this issue. One legitimate fear is that the range of social tolerance for personality types and traits will be narrowed excessively to the detriment of such individuals. That is, those individuals may be subjected to excessive social scrutiny and social pressure to conform to a narrow range of socially acceptable behavior. This seems contrary to the core values of a liberal society. However, in other cases medicalization of behavior that once was regarded as normal may be beneficial to both individual and social welfare. Attention deficit hyperactivity disorder (ADHD) illustrates this point. Children who are identified as having ADHD benefit greatly from drugs such as Ritalin. The practical moral problem is that the behavioral and diagnostic boundaries of this disorder are fuzzy and controversial, and this can lead to morally troubling problems of overdiagnosis and underdiagnosis.
The other concern raised by the Nuffield Council is the eugenics issue. Dean Hamer and coworkers announced in 1993 the discovery of "the gay gene." Hamer later retracted that claim, recognizing that the basis for the sexual orientation of individuals is much more complex than the workings of a single gene. However, his original claim helped establish in the public mind that there soon may be a genetic test for "being gay" that would allow potential parents in the future to use preimplantation genetic diagnosis (PGD) to weed out gay embryos. Similar beliefs suggest that in the future it will be possible to pick out or create through germline genetic engineering smarter or happier or nonviolent or nonalcoholic embryos. This refers back to the eugenics issues that were raised earlier in this entry.
Those issues may be addressed more thoughtfully by recalling a key scientific claim about behavioral genetics. These types of behavioral phenomena are only indirectly the product of very complex interactions among many genes as well as environmental factors, all of which are very poorly understood. Nobody knows which genes, in what way, to what degree, and at what point in development yield the neural capacities that establish a range of intellectual abilities. This is true whether one's concerns are with happiness, aggressiveness, schizophrenia, or addiction (Hamer; Beckwith and Alper). Furthermore, if society's legitimate social goals include shaping human behavior in various ways, there also are available as tools a very large range of social practices and medical interventions.
Behavioral Genetics and Eugenics: Some Ethical Guidelines
The Nuffield Council on Bioethics) has suggested several criteria for assessing from a moral point of view eugenic interventions aimed at improving behavioral outcomes: effectiveness, safety, reversibility, and choice.
If researchers discover genes associated with intelligence, it is likely that any one of those genes will have only very small and uncertain effects on the intellectual potential of an embryo. Consequently, embryonic genetic intervention to improve intelligence appears to be an ineffective approach. IQ scores as measured by standardized tests increased twenty to thirty points during the twentieth century. Clearly, that improvement did not result from radical genetic changes.
Safety must be a critical moral consideration, especially if the individuals whose behavior is to be affected do not have the capacity to give consent, as would be true for children and embryos. Giving Paxil to a moderately shy child may be morally objectionable when researchers are not certain of the long-term effects of that drug and the behavior to be altered is only moderately dysfunctional. Gene therapy would be problematic on this criterion for children or adults because there has been little success and some serious bad outcomes. The risks of gene therapy may be reasonable if individuals are faced with a life-threatening disorder, but that is not the case when the goal is behavioral alteration.
Reversibility is the third criterion the Nuffield Council emphasizes. It is difficult to imagine that anyone would want to be less intelligent, less happy, vulnerable to addiction, or more prone to violence. However, if researchers engage in behaviorally oriented genetic alterations, they may over-shoot the mark: An individual could end up experiencing feelings of happiness in socially inappropriate situations.
The Nuffield Council notes that physicians are very reluctant to do genetic testing of children for medical disorders to which a child might be vulnerable as an adult and for which there is no medical intervention. The council recommends similar reticence if genetic tests related to what might be described as presymptomatic personality disorders were developed.
For example, a child might seem as happy as any other child in the neighborhood, but parental concerns about a family history of depression might motivate them to pursue genetic testing of that child for depression. That testing would yield no obvious good for the child but could put the child at risk for stigmatization or a maladaptive response from the parents. In addition, such nonsymptomatic nontherapeutic genetic testing represents a violation of the privacy rights and autonomy rights of that child. Also, assuming that the test identified a genetic pattern associated with depression in the child's family, everything known today would suggest that this represented no more than increased susceptibility for that disorder, not certainty that it would express itself or that its expression would be severe.
There are considerations of justice and the protection of fair equality of opportunity that are relevant to this discussion. Some writers (Silver) fear that differences in wealth will permit the rich to purchase a superior genetic endowment, especially with regard to valued behavioral traits, for their children, establishing permanently superior genetic castes. However, this is a plausible concern only extremely far into the future, if ever.
Still, there are relevant considerations of justice in the present that are related to improving the genetic endowment of future children (Fleck). Genetic testing in vitro of eight-cell embryos, or preimplantation genetic diagnosis, permits the selection of embryos that are free of certain serious genetic defects. However, this intervention costs about $40,000 per successful pregnancy. It seems reasonable to ask whether such interventions should be publicly funded as a matter of social justice and perhaps as a matter of genetic social responsibility as well.
Relative to scientific understanding and technical capacities in the field of behavioral genetics, fears of behavioral eugenics are exaggerated. People have very little capacity, using the tools of molecular biology, to alter with confidence the genetic endowments of future children.
No emerging knowledge in the fields of behavioral genetics and developmental biology or the neurosciences would justify concluding in a global fashion that human beings can no longer be held morally responsible for their behavior because their behavior has been determined in a mechanistic fashion by their genes (Wasserman).
However, as knowledge of the behavioral sciences becomes more refined and certain, society will be forced to make increasingly nuanced judgments about the capacity for responsible moral action by individuals whose genetic endowment includes significant susceptibility to aggression or depression or other socially or medically deviant behaviors. That is, society will have no right to advance global assertions of moral responsibility by all individuals in all circumstances. In some circumstances moral or legal responsibility for specific actions will be diminished or eviscerated as a result of biological facts beyond the control of the individual.
A liberal society should accord substantial respect for the procreative liberty of potential parents, including their right to determine the genetic endowments of their future children. However, a responsible liberal society will take seriously its obligations to protect those children from embryonic behavioral genetic experimentation that would threaten their future capacities for autonomy or the future interests generally valued by all human beings. No simple moral algorithm can indicate how such balances should be struck in making public policy.
richard a. shweder (1995)
revised by leonard m. fleck
SEE ALSO: Autonomy; Freedom and Free Will; Genetic Counseling, Ethical Issues in; Genetic Counseling, Practice of; Genetic Engineering, Human; Genetics and Environment in Human Health; Genetics and Human Self-Understanding; Genetics and Racial Minorities; Genetics and the Law; Human Dignity; Human Nature;Privacy and Confidentiality in Research; and other Genetics and Human Behavior subentries
Beckwith, Jon, and Alper, Joseph. 2002. "Genetics of Human Personality: Social and Ethical Implications." In Molecular Genetics and Human Personality, ed. Jonathan Benjamin, Richard Ebstein, and Robert Belmaker. Washington, D.C.: American Psychiatric Publishing.
Duster, Troy. 1990. Backdoor to Eugenics. New York: Routledge.
Ehrlich, Paul, and Feldman, Marcus. 2003. "Genes and Cultures: What Creates Our Behavioral Phenome?" Current Anthropology 44: 87–95.
Evans, John H. 2002. Playing God: Human Genetic Engineering and the Rationalization of Public Bioethical Debate. Chicago: University of Chicago Press.
Fleck, Leonard. 2002. "Just Caring: Do Future Possible Children Have a Just Claim to a Sufficiently Healthy Genome?" In Medicine and Social Justice: Essays on the Distribution of Health Care, ed. Rosamond Rhodes, Margaret Battin, and Anita Silvers. New York: Oxford University Press.
Hamer, Dean. 2002. "Rethinking Behavior Genetics." Science 298: 71–72.
Hamer, Dean; Hu, S.; Magnusun, V.; and Pattatucci, A. 1993. "A Linkage between DNA Markers on the X Chromosome and Male Sexual Orientation." Science 261(5119): 321–327.
Jamison, Kay Redfield. 1995. An Unquiet Mind: A Memoir of Moods and Madness. New York: Vintage Books.
Jensen, Arthur. 1969. "How Much Can We Boost IQ and Scholastic Achievement?" Harvard Educational Review 39(1): 1–123.
Kass, Leon. 2002. Life, Liberty, and the Defense of Dignity: The Challenge for Bioethics. San Francisco: Encounter Books.
Kevles, Daniel. 1985. In the Name of Eugenics: Genetics and the Uses of Human Heredity. Berkeley: University of California Press.
Kitcher, Philip. 1996. The Lives to Come: The Genetic Revolution and Human Possibilities. New York: Simon & Schuster.
Lemonick, Michael. 2003. "The Search for a Murder Gene." Time, January 20, p. 100.
Murray, Charles, and Herrnstein, Richard. 1994. The Bell Curve. New York: Free Press.
Nuffield Council on Bioethics. 2002. Genetics and Human Behavior: The Ethical Context. London: Nuffield Council on Bioethics.
Parens, Eric, ed. 1998. Enhancing Human Traits: Ethical and Social Implications. Washington, D.C.: Georgetown University Press.
Peters, Ted. 1997. Playing God: Genetic Determinism and Human Freedom. New York: Routledge.
Pinker, Steven. 2002. The Blank Slate: The Modern Denial of Human Nature. New York: Viking.
Rawls, John. 1993. Political Liberalism. New York: Columbia University Press.
Ridley, Matt. 1999. Genome: The Autobiography of the Species in 23 Chapters. New York: HarperCollins.
Rifkin, Jeremy. 1984. Algeny. New York: Penguin Books. Schaffner, Kenneth. 1999. "Complexity and Research Strategies in Behavioral Genetics." In Behavioral Genetics: The Clash of Culture and Biology, ed. Ronald Carson and Mark Rothstein. Baltimore: Johns Hopkins University Press.
Silver, Lee. 1997. Remaking Eden: Cloning and Beyond in a Brave New World. New York: Avon Books.
Wasserman, David. 2001. "Genetic Predispositions to Violent and Antisocial Behavior: Responsibility, Character, and Identity." In Genetics and Criminal Behavior, ed. David Wasserman and Robert Wachbroit. Cambridge, Eng., and New York: Cambridge University Press.
"Genetics and Human Behavior: II. Philosophical and Ethical Issues." Encyclopedia of Bioethics. . Encyclopedia.com. 19 Jan. 2019 <https://www.encyclopedia.com>.
"Genetics and Human Behavior: II. Philosophical and Ethical Issues." Encyclopedia of Bioethics. . Encyclopedia.com. (January 19, 2019). https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/genetics-and-human-behavior-ii-philosophical-and-ethical-issues
"Genetics and Human Behavior: II. Philosophical and Ethical Issues." Encyclopedia of Bioethics. . Retrieved January 19, 2019 from Encyclopedia.com: https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/genetics-and-human-behavior-ii-philosophical-and-ethical-issues