Ladies, Check Their Alleles

Tue, 02 Sep 2008 12:56:53 +0000

Tantalizing news about your genes (at least, if you are a guy) in The Washington Post yesterday:

MONDAY, Sept. 1 (HealthDay News) -- Whether a man has one type of gene versus another could help decide whether he's good "husband material," a new study suggests.

A study of Swedish twin brothers found that differences in a gene modulating the hormone vasopressin were strongly tied to how well each man fared in marriage.

"Our main finding was an association between a variant of the vasopressin receptor 1a gene and how strong bonds men reported they had to their partners," said lead researcher Hasse Walum, of the department of medical epidemiology and biostatistics at the Karolinska Institute in Stockholm. "Men carrying this variant scored on average lower on a scale measuring the strength of the bond compared to men not carrying this variant."

Women married to men carrying the "poorer bonding" form of the gene also reported "lower scores on levels of marital quality than women married to men not carrying this variant," Walum noted.

I am frustrated by the way this article reports the scientific finding. The pitch to the reader is about the existence of the gene. Why is that news? Was there someone out there who thought that "how well each man fared in marriage" bore no relation to his genetic makeup? The key questions are which genes (partially answered in this study) and to what extent. It is in the latter that the reporting is weak. Consider this excerpt from later in the article:

So, it's too early for men to blame their inability to commit on a single gene, although Lucas guesses it's an excuse that's "certainly going to be used."

For his part, Walum agreed that men and their spouses shouldn't read too much into the finding.

"Taken together, the effect of the gene variant that we have studied on human pair-bonding behavior is rather small, and it can not, with any real accuracy, be used to predict how someone will behave in a future relationship," he said.

If that last sentence is true, then why publish the study? In order for it to be a finding, there had to be predictive power of something. So tell us what it is. Don't hide behind "rather small." It was rather large enough to be published, after all. The Post ran another story today. Look how much better the introductory paragraphs are:

Men are more likely to be devoted and loyal husbands when they lack a particular variant of a gene that influences brain activity, researchers announced yesterday -- the first time that science has shown a direct link between a man's genes and his aptitude for monogamy.

The finding is striking because it not only links the gene variant -- which is present in two of every five men -- with the risk of marital discord and divorce, but also appears to predict whether women involved with these men are likely to say their partners are emotionally close and available, or distant and disagreeable. The presence of the gene variant, or allele, also seems predictive of whether men get married or live with women without getting married.

"Men with two copies of the allele had twice the risk of experiencing marital dysfunction, with a threat of divorce during the last year, compared to men carrying one or no copies," said Hasse Walum, a behavioral geneticist at the Karolinska Institute in Stockholm who led the study. "Women married to men with one or two copies of the allele scored lower on average on how satisfied they were with the relationship compared to women married to men with no copies."

Now we know. I don't think a factor of two is "rather small."