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Our Deterministic DNA: Another Media Myth

There’s nothing new in the idea that people tend to resemble their parents (and other relatives), in both looks and personality. Has the discovery of the gene as the means of transmission simply changed the way we express this familiar idea? (After reading their father’s school reports, my children claimed to have inherited the “could-do-better” gene.) Or does the discovery of connections between certain genes, or, more precisely, certain variants of genes, and particular behavioral traits, change the way we think about moral responsibility and free will?

I was washing dishes recently, and caught part of an episode of some television program featuring Barbara Walters and various other women talking about this precise issue. Walters suggested that as we learn more about the role genes play in our lives – from high blood pressure to obesity to aggression – we’re likely to think that we’re less responsible for the way we are. Characterizing this view, she said, “I used to think it was me, and now I realize it’s my genes.”

At that point, I turned off the television, for fear of losing IQ points. I mean, really. Does she think that my genes are alien forces, somehow inhabiting my body, and compelling me to act in certain ways? Little microchips that have been implanted by sinister beings? To contrast “me” and “my genes” is deeply absurd. Of course, genes are not the whole story, but to the extent that genes play a causal role, they are as much “me” as anything else that explains why I am the way I am.

Behavioral geneticists understand that all complex human behaviors are a product of both genes and environment. They would like to find out how much is due to genetics, and how much to the environment. But this question, which lies at the heart of behavioral genetics, sets up a simplistic and unrealistic dichotomy between the genes and the environment. The reality is that which genes are expressed is often extremely complex, both because of numerous interactions between multiple genes and because which genes are expressed is often a function of the environment. For example, one study found that boys who had a particular gene variant (MAOA) were significantly more likely to be engaged in criminal behavior than other boys, but only if they had been the victims of moderate to severe abuse in childhood. In the absence of abuse, boys with this gene were no more likely to get in trouble with the law than boys who did not have it. This is a perfect example of how the expression of a genetic trait may depend on an environmental factor.

Nor is there any reason to think that if having the MAOA gene plays a causal role in anti-social behavior, the right response is genetic modification. Why not try and figure out how to reduce child abuse? This is as much a causal factor, I presume, in kids getting into trouble in school or with the law as having a particular genotype.  Having violent parents is as much out of one’s control as the genotype one inherits. So why should we think that genes are these all-controlling, immutable factors that determine who we are and what we’re like? The truth is that neither genes nor environment determines what anyone will be like, though both may predispose us to a variety of traits and behaviors. Whether the existence of causal factors, genetic or environmental, makes us unfree is an age-old question, and the answer depends on what you mean by “free.” But increased knowledge about one kind of causal factor – genes – does not change that debate one whit. It would be wonderful if the public could understand this, and if television personalities did not obscure the issue even further.

Bonnie Steinbock teaches philosophy at the University at Albany, SUNY.

Published on: June 27, 2006
Published in: Emerging Biotechnology, Media

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