The link between adolescents' experiences of parental favouritism and differences in sibling communication patterns during interactions with their sibling is examined. One hundred and seventy five adolescent, twin sibling pairs and their parents were involved in the study. The findings suggest that twins' non shared experiences of differential parenting in the family are linked to both twins' shared experience of destructive patterns of communication during conflict with their twin, and to non shared experiences in their relational communication with their twin. The implications of these findings for parenting and the transmission process of communication patterns and conflict across familial relationships is discussed. (Author abstract, edited)