Several years ago while I was a graduate student, I was an archaeological intern with the environmental conservation office at Vandenberg Air Force Base. I lived in Goleta, which is immediately north of Santa Barbara, meaning that, on the days when I had to be on base (3-4 days a week, depending on what was happening) I would listen to the radio on my drive in (this was in the days before I owned an iPod or had discovered podcasts).
The only radio station that I could reliably listen to for the entire drive was the Santa Barbara pop station, and they had a predictable morning show - the allegedly wacky DJs would play music and jabber on about whatever wacky thing that they could think of, while inviting callers to call in and voice their own opinions.
On one particular morning, the DJs had brought up the subject of a recently published paper that was getting a lot of press. The radionistas were stating that the paper reported a study in which researchers found that sexual infidelity was caused by genes. They asked their callers to talk about whether or not they thought that infidelity was caused by genetics, and the calls that came in were every flavor of over-generalization. There were the people who were absolutely convinced that infidelity was genetic because they knew one person who was a cheater who had a parent who was also a cheater (yeah, must be genetic, couldn't possibly be a learned behavior, nope, not at all), or who were absolutely convinced that that it wasn't genetic because they knew one person who was not a cheater, but who had a parent that was. And then there were the usual parade of clowns who assured everyone who would listen that it wasn't genes but rather people "moving away" from amorphous and ill-defined "old fashioned family values" of the past*. All the while, the DJs kept announcing that "science has proving that infidelity is caused by genes."
What the DJs were attempting to discuss was this study which looked at the sex lives of both identical and non-identical twins in an effort to identify whether or not there was a genetic component to sexual infidelity. There have since been other studies on the same subject and they have found what appears to be a genetic component to infidelity, though in each study, including the 2004 one, the findings have been rather more complicated than was being reported in the mass media.
What the early study actually found was that there was a correlation between people's genetic similarities and their sexual behavior. Identical twins (twins with identical DNA) had the most similarity as regards cheating, while non-identical twins (twins who have no more DNA in common than any other set of siblings) had less in common. Subsequent studies have found similar results, and researchers are working on identifying whether or not particular sets of genes provide a causal mechanism that increases the likelihood of infidelity**. So, the study indicated a genetic element to infidelity, but did not prove one, which is typical of science, where complex issues take a long time to work out.
The study also did not rule out social causes and learned behavior as the triggers to infidelity. This is a point that many people don't get - there is an assumption that genes are just on/off switches, and that if someone has a particular set of genes then they will have a particular set of physical and psychological traits. This is simply not true. Genes code for traits, yes, but the way in which traits are expressed is often influenced by the environment. This is true of physical traits, but seems to be especially true of psychological traits due to the sheer complexity of the human brain***. So, even if one has genes that code for infidelity, that doesn't mean that infidelity is inevitable, or even likely. It means that there is a higher percentage chance of cheating, but so many factors influence such behavior that there is no reason to assume that someone with these genes is a cheater - individuals will express the genes in individual ways, but these may not include infidelity but may indicate some other form of behavior that isn't damaging to a relationship.
Before I even saw the study or any of the reporting on the study I immediately started thinking that the study probably reported something similar to what is, in fact, what the study actually did conclude, and which is radcially different from what was being said by the DJs. Simply understanding how science works immediately caused me to question what was being said on the radio, and following-through with looking up the study indicated that my skepticism of the "genes cause infidelity" claim were well-founded.
Now, many people will say "hey, it was a dumb morning show, don't worry about it." The problem is that, yes it was a dumb morning show, but the listeners now have been informed that infidelity is caused by genetics, and have had the notion that genes are destiny (rather than one of several causal factors in behavior) reinforced. And the research shows pretty strongly that new information, provided that it doesn't conflict with existing beliefs, tends to simply become part of the background noise in a person's memory that will be called on whenever the subject comes up, but never evaluated to closely for its validity. And here was the most-listened to radio show in Santa Barbara County announcing that scientists had "proven" that infidelity is genetic. For most people listening this was probably the first that they had heard about a link between genetics and sexual behavior, and as such it is the (mis)information on which they were likely to base their future opinions on this matter.
Worse, people who heard this show might start to be prejudiced in their opinions of people based on the activities of those people's relatives. In short, this sort of claim is likely to provoke what might be termed a "genetic bigotry" where the sins of the parent, or sibling, or cousin, etc. might be held against someone innocent of any wrong-doing.
When I arrived home that evening, I sent an email to the radio station expressing my disappointment in the show. I explained that the study in question didn't actually reach the conclusions that they were claiming that it did, and that by handling this the way that they did, they not only failed to inform their audience about the real science, they actually mis-informed their audience and increased their audience's ignorance of the issue.
There was some email back-and-forth between myself and the DJs, with them saying "hey, we were trying to educate" and me trying to explain that they did the exact opposite. In the end I asked them to consider that, if they felt that they were unable to accurately discuss the science, then perhaps it was best to not bring it up at all. After all, there's no end of oddball news stories for a morning show to cover.
I don't know if my response to them would have had an effect. Shortly after this incident, the radio station changed formats and the DJs found themselves out of a job.
However, this has long been a frustration of mine when listening to any media reports, whether from a news or an entertainment show, about research. The conclusions are pretty much always mis-reported, the methods rarely described, and the underlying issues (in this case, do genes cause behavior or merely make it statistically more likely) rarely are discussed.
*This "old fashioned family values" line has always bothered me for a very basic reason. Many of the things that people who trumpet this claim are new, such as infidelity, are not new at all. The simple fact of the matter is that we talk about these things more, giving the impression that they are now more common, but there is in fact very little reason to believe that they are any more prevalent now than they were 20, 30, 40, 50, 60, 70 years ago. In fact, because they are spoken of more nowadays, they may be easier to spot, and might actually become less prevalent as a result - but that's just speculation on my part.
**This is important as there are a few different reasons why identical twins might share behavioral traits that are not related to their genetics, as identical twins are often socialized somewhat differently than those of us who do not have an identical twin. The fact that non-identical twins do not share this trait as often as identicals does suggest a genetic cause, but social causes can not be ruled-out until a definite causal mechanism can be determined.
***And, really, as psychological traits spring from the brain, which is a physical entity, these are also physical traits, just very subtle, complex ones.