A twin study explored the possible genetic influences on gambling behavior. Male monozygotic (MZ) twins (n = 42) revealed significantly greater similarity on gambling frequency associated with "high-action" games than male dizygotic (DZ) twins (n = 50). The heritability estimates for involvement in these types of games among males were moderate and significant. All MZ versus DZ comparisons among males for "low-action" games were nonsignificant, as were MZ versus DZ comparisons among females (n = 63) for both types of games. The findings suggest that genetic influences may be important in the origins of certain types of gambling by men.
