Family relationships begin to develop during pregnancy and provide the context for a child’s early social-emotional development. However, the contribution of parental prenatal representations and early parent–child relationships, particularly those of fathers, are less studied. This thesis examined the associations between fathers’ and mothers’ prenatal representations, early parent–child interaction, triadic family interaction, and the early social-emotional development of children in two-parent families, with particular emphasis on early father–child relationships. The data were collected as part of the multidisciplinary Steps to the Healthy Development and Well-being of Children cohort study. Families (n = 153) were followed from pregnancy until the child was 18 months old.

The aims of this thesis were to examine 1) associations between fathers’ prenatal representations and postnatal father–child interaction (Study I), 2) the change and stability in father–child interaction from infancy to toddlerhood (Study I), 3) associations between dyadic parent–child interaction and triadic family interaction (Study II), and 4) fathers’ and mothers’ prenatal representations and their associations with a child’s social-emotional development (Study III). The results showed that fathers’ balanced prenatal representations were associated with higher quality in early father–child interaction. Both positive changes and moderate stability in dyadic father–child interaction were observed from infancy to toddlerhood. Well-functioning parent–child interaction, particularly between fathers and children, was associated with higher family coordination and cooperative family alliance in toddlerhood. In addition, both parents’ balanced prenatal representations were associated with higher social-emotional competence in children.

The findings of this thesis highlight the importance of balanced prenatal representations and well-functioning early parent–child relationships. Both father–child and mother–child relationships play essential roles in shaping triadic family interaction and enhancing a child’s early social-emotional competence.