Parent Characteristics and Early Coparenting Behavior at the Transition to Parenthood Sarah J. Schoppe-Sullivan 1 and Sarah C. Mangelsdorf 2 1 The Ohio State University 2 Northwestern University Abstract This study examined parent characteristics as correlates of coparenting behavior in 57 primiparous couples. Parents’ negative emotionality and perceptions of maternal acceptance in childhood, mothers’ beliefs about fathers’ roles, and observed marital behavior and family socioeconomic status were assessed during the third trimester of pregnancy, and coparenting behavior was observed at 3.5 months postpartum. Couples who exhibited high-quality marital interaction showed higher supportive coparenting behavior, but couples who showed lower quality marital interaction demonstrated higher supportive coparenting behavior when mothers held more progressive beliefs about fathers’ roles. Couples showed more undermining coparenting behavior when family socioeconomic status was lower and when fathers were higher on negative emotionality. Greater perceived maternal acceptance in childhood was only associated with lower levels of undermining behavior when prenatal marital interaction was high in quality. Thus, the characteristics of both parents, especially in combination with preexisting marital behavior, are important determinants of coparenting behavior. Keywords: coparenting; parent characteristics; marital interaction; transition to parenthood Introduction For couples anticipating the birth of their first child, a critical task is the development of an effective coparenting relationship. Coparenting can be defined as the extent to which parents support each other’s parenting or fail to do so and consists of several components (Feinberg, 2003): supportive (warm and cooperative) and undermining (hostile, critical, and competitive) behavior between parents, the division of childcare labor (how childcare is divided and satisfaction with this division), joint family man- agement (control of family boundaries and interactions), and agreement about parent- ing topics (e.g., moral values and behavioral expectations). The notion of coparenting Correspondence should be addressed to Sarah Jane Schoppe-Sullivan, Human Development and Family Science,The Ohio State University, 131 Campbell Hall, 1787 Neil Avenue, Columbus, OH 43210, USA. Email: schoppe-sullivan.1@osu.edu Social Development Vol •• No. •• ••–•• •• 2012 doi: 10.1111/sode.12014 © Blackwell Publishing Ltd. 2012. Published by Blackwell Publishing, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main Street, Malden, MA 02148, USA.