D. Angus Clark

Background: Prior work suggests girls with earlier subjective pubertal timing (i.e. girls who perceive themselves as maturing earlier than peers) engage in more antisocial behavior (ASB). Theories regarding mechanisms predominantly focus on social/environmental processes, but genetic influences may contribute, particularly given that ASB is heritable, and the stress associated with earlier subjective timing may activate or enhance these genetic vulnerabilities to increase risk. To date, no study has examined these gene × environment interactions (G×E) for ASB and subjective pubertal timing relative to peers. Methods: Participants included 995 female twins (ages 8–16 years) from the MSU Twin Registry. Mothers reported children’s aggressive and rule-breaking behaviors using the Child Behavior Checklist. Subjective timing was assessed with a modified Pubertal Development Scale where twins reported their maturation on pubertal markers (e.g. breast development) as earlier, the same, or later compared to two reference groups: their co-twin and other girls their age. Results: Twin models revealed that genetic influences on aggression and rule breaking were stronger in earlier versus on-time and later-maturing girls. These effects were present when examining timing relative to co-twin and other girls, although effects were somewhat stronger for co-twin. Environmental influences on aggression and rule breaking were greater in later-maturing girls across both reference groups. Conclusions: Results significantly inform etiologic models by highlighting G×E for associations between subjective timing and ASB in girls. Findings underscore the importance of considering genetic influences and the need to further explore the specific genetic/environmental factors that shift across perceptions of pubertal timing.