in the early life course by positive parenting. Thus, the comparison of social and genetic influences in adolescent behavior is something of a false dichotomy. Gene/environment interactions are apparent throughout life. For example, individuals vary in genetic propensity for nicotine addiction and obesity, and these genetic propensities may interact with exposure to social factors (e.g., marriage, parenting) in ways that trigger or accelerate these propensities at any point in the life course and especially in critical periods (Hernandez & Blazer 2006). Given the heritability of many personality traits and the impact of personality on social ties and health habits, one potentially fruitful line of research concerns gene/environment interactions involving personality traits.
