Prenatal folate and vitamin B[subscript 12] status have been linked to child neuropsychological development, but less is known about maternal genetic influences on this association. We conducted an exploratory longitudinal study of 181 mother--child pairs to assess whether maternal MTHFR 677C>T genotype modifies the association between maternal…

Exposure to deviant friends has been found to be a powerful source of influence on children's and adolescents' aggressive behavior. However, the contribution of deviant friends may have been overestimated because of a possible non-accounted gene-environment correlation (rGE). In this study, we used a cross-lagged design to test whether friends'…

The associations between parenting practices and adolescent anxiety symptoms were examined in both individual and monozygotic (MZ) twin differences levels. Participants were 804 pairs of Chinese MZ adolescent twins aged 10-18 years (M = 13.57, SD = 2.67, 52% females). Twins' anxiety symptoms were assessed by self- and parent-reports. Twins also…

This study used a genetically controlled design to examine the direction and the magnitude of effects in the over-time associations between perceived relationship quality with mothers and adolescent maladjustment (i.e., depressive symptoms and delinquency). A total of 163 monozygotic (MZ) twins pairs (85 female pairs, 78 male pairs) completed…

Most of the individual difference variance in the population is found "within" families, yet studying the processes causing this variation is difficult due to confounds between genetic and nongenetic influences. Quasi-experiments can be used to test hypotheses regarding environment exposure (e.g., timing, duration) while controlling for…

The concept of bidirectionality represents a process of mutual influence between parent and child, whereby each influences the other as well as the dyadic relationship. Despite the widespread acceptance of bidirectional models of influence, there is still a lack of integration of such models in current research designs. Research on…

There has been significant interest in examining the developmental factors that predispose individuals to chronic criminal offending. This body of research has identified some social-environmental risk factors as potentially important. At the same time, the research producing these results has generally failed to employ genetically sensitive…