Author: Sheldon Krimsky

A Response to Boutwell and Anomaly’s “Why Sex (Really) Matters”

The essay by Anomaly and Boutwell begins by emphasizing the importance of sex and ends by asserting that sex and reproduction are done for different reasons and I would add increasingly by different methods. These statements are generally recognized as true. However their statements about heritability, the genetic basis of behavior, and IQ are regrettably ill-informed, exaggerated or trivialized and are not grounded in good or consensus science. Let’s take heritability. It is a population measurement of a proportion, namely the measurement of a variation in a phenotype (physical characteristic or behavior) due to a genetic variation in a population. So if we have genetically identical plants (no genetic variation) and we find a variation in their heights, then the heritability is zero. H2 =   Var (G)/Var (P). The concept of heritability refers only to traits that differ among individuals. A trait that is exactly the same may be inherited, but it is not heritable. Also, heritability tells us nothing about individuals. Also, you cannot measure heritability without studying the environment. By changing the environment, …