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We have heard about the God gene and the gay gene -- though each has been met with significant skepticism. Now comes news of a gene that Swedish researchers are touting as a possible biological basis for why some guys won't settle down.

Credit a young researcher at Sweden's Karolinska Institute for discovering a link between a variation in the AVPR1A gene -- which has been linked to autism and how people interact socially -- and a propensity for men to skip out on women, or to have marital problems if they do tie the knot.

In a photograph on the Karolinska's website, the researcher, Hasse Walum, looks a little like rocker Kurt Cobain.

Walum did not report if he carries the tell-tale gene, although in a study of 552 sets of twins, all in relationships, Walum found that 40 percent of the men carried the Ramblin' Man variation of this gene.

The couples filled out questionnaires that asked questions such as:

Researchers then ran genetic screens of the subjects, discovering that a line of code at position 334 in the gene had a statistical correlation with the less committed men.

Women married to men who carry one or two copies of the suspect code were, on average, "less satisfied with their relationship" than were women married to men who didn't carry this code, Walum said.

This same gene has also been linked in a different study to dictatorial behavior, and the hormone, called vasopressin, made by this gene has been found to be plentiful in voles that mate for life.

But before women rush out to test their men for this genetic variation -- or we run DNA screens of John McCain and Barrack Obama to see if they have an autocratic bent hidden in their genes -- we need to realize that these tests are very preliminary statistical links. No one has physiologically linked this genetic variation to behavior in a relationship, or to Stalinistic behavior.

Walum is well aware of this, and pointed out that the effect of the genetic variation is "modest," and cannot be used to predict the future behavior of someone in a relationship.

A caveat that makes one wonder why researchers, institutes, and the media keep trotting out these preliminary associations between genes and profoundly important human behaviors like religion and relationship management in this way.

One reason is that they can be fun, like reading Tarot cards can be fun. These studies can also point scientists in a possible direction towards where to look for serious maladies such as autism, which is what Walum's work is focusing on.

"There are, of course, many reasons why a person might have relationship problems," Walum told the BBC.

Indeed, there are.