Can one gene make a difference?  Absolutely.  One case in point is Tay-Sachs Disease, a physical condition  where the central nervous system begins to degenerate in a four to six month old child who, until the onset of the disease, appeared normal.  Individuals with Tay-Sachs disease have two copies of a genetic mutation, one copy inherited from each parent.  In a carrier of Tay-Sachs, only one gene is different when compared to non-carriers. That’s how important one gene can be.   When we’re talking about complex behaviors, though, can the “cause” really boil down to one gene?  It’s unlikely.

I recently had the opportunity to attend several sessions of the “Future Directions in Genetic Studies” workshop at Washington University in St. Louis. On Friday, I attended a lively seminar led by Gar Allen, who teaches biology at Washington University. His talk was entitled “What’s Wrong with ‘The Gene for . . .’? Problems with Human Behavior Genetics and How to Combat Them.”

Allen opened his talk by asserting that claims about the genetic basis for complex human behaviors and traits are “notoriously difficult to investigate and replicate.” There is a long and troubled history of claims that genes are the cause of various conditions. For instance, in 1969, Arthur Jensen became the center of a storm when he wrote that Caucasians were more intelligent than African-Americans, suggesting that there was a genetic basis for this difference. Jensen’s position has been heavily criticized by numerous scientists on numerous …