The current UK/Europe edition of the Economist is running an article on research that associates certain genetic features with a tendency to develop a liberal or conservative political attitude. The researchers they quote suggest that a combination of a specific variation in DRD4, the source of a dopamine receptor, with certain environmental influences, such as having lots of friends, means that a person is much more likely to be liberal than conservative, although many other factors (such as financial stress) can easily cancel this effect out.
The idea of genetics predicting or controlling personal behaviour is a difficult path to tread without falling into social, moral, ethical, or political territory that lies within all too easy reach, but if a gene does indeed exist that can be used to predict voting tendencies, imagine then what metagenomics studies could do to future elections. If it were possible to reliably extract only human DNA from the sludge that arrives at sewage treatment plants and analyse the relative concentration of such genes in the population covered by the pipes, then any election result in the local area could reliably be predicted without needing to bother with actual votes.
OK so that is rather far-fetched and more than a little Orwellian. But it is precisely this kind of nightmare scenario that we have to be so careful to avoid creating in the process of genetics research.
There does come a point where the question has to be asked: why do we need to know? Sure it is interesting to find out that DRD4 is implicated in political decision making, but who does that information help, and to what end? Why did we even bother asking the question in the first place? As with much other research in this field, it is likely that the specific question was not particularly of interest, but the general class of questions relating to the connection between genetics and behaviour would be better understood by researching a single example. Of course, a popular or controversial example would increase chances of media coverage and thus future grant opportunities, but was that necessary? Does knowing that genetics can influence personal behaviour and decision making solve any known problems, or does it simply cause more problems by opening up the possibility of using genetic tests to excuse people from taking responsibility for their own actions? (Or worse, to predict their actions and act upon them before they have even happened.)