Psychological traits are highly heritable

This is from 2004 but the evidence has become even stronger since then. From Genetic Influence on Human Psychological Traits: A Survey by Thomas J. Bouchard, Jr. Subject to gross mischaracterization by advocates across the policy spectrum, but useful to know. Abstract.

There is now a large body of evidence that supports the conclusion that individual differences in most, if not all, reliably measured psychological traits, normal and abnormal, are substantively influenced by genetic factors. This fact has important implications for research and theory building in psychology, as evidence of genetic influence unleashes a cascade of questions regarding the sources of variance in such traits. A brief list of those questions is provided, and representative findings regarding genetic and environmental influences are presented for the domains of personality, intelligence, psychological interests, psychiatric illnesses, and social attitudes. These findings are consistent with those reported for the traits of other species and for many human physical traits, suggesting that they may represent a general biological phenomenon.

In chart form:

Click to enlarge.