OBJECTIVEUsing quantitative genetic analysis of twin study design to explore the impact of genetic and environmental factors on the prosocial behaviors of children.

METHODSOne hundred and forty-seven twin pairs from Chengdu area aged 6-16 were studied using parental information of Strengths and Difficulties Questionnaire (SDQ). SPSS13.0 and Mx software were used to analyze data, including nonparametric test, Pearson correlation, genetic analyses, etc.

RESULTS(1) Female children score higher than males on their prosocial behavior (Ps< 0.05), except less than 11 age group; (2) Shared environmental factors were the most important for children's prosocial behaviors(C=0.48,95%CI:0.09-0.73),then the genetic factors (A=0.27,95%CI:0-0.66) and the unshared environmental factors(E=0.25,95%CI:0.18-0.35); (3)Female and those who scored higher on their fact/ideal family adaptability and cohesion scored higher in their prosocial behaviors (r:0.17-0.29). On the contrary, those who had extreme conditions during pregnancy/ perinatal period or whose caretaker had discordant opinions on parenting scored lower (r: -0.16 to 0.28).

CONCLUSIONChildren's prosocial behaviors were influenced by genetic and environmental factors including family function and parenting environment, and genetic impact differs in different age and sex.