It has been suggested that parenting (i.e., parenting behaviours directed toward children) is passed through the generations. However, rigorous evaluation of intergenerational (IG) continuity (i.e., similarities/differences in mean levels of parenting behaviours across generations) and stability (i.e., associations between parents and children’s parenting behaviours) of parenting is lacking. Substantial gaps in existing evidence remain regarding which parenting behaviours are transmitted, when in development transmission occurs and what process underly continuity and discontinuity of IG transmission. Furthermore, longitudinal research that examines associations between parenting in one generation (e.g., G0; grandparents), parenting of the next generation (G1; parents) and developmental and mental health in their offspring (G2; grandchildren) is very limited. Insights into these questions are crucial for targeted intervention and prevention programmes to address IG continuity and stability of parenting to improve offspring developmental and mental health outcomes in the next generation.

Existing evidence-base regarding IG transmission of parenting and its role in intergenerational transmission of mental health risks is extremely limited. Most studies are retrospective, while prospective three-generational studies that utilise data from three generations (G0/Grandparents->G1/Parents->G2/Grandchildren) are acutely lacking. Relatedly, most evidence is based on retrospective rather than prospective reports of parenting, which may be prone to recall and reporting bias, particularly in the context of parental depression. IG transmission has been mostly examined in the context of maltreatment and harsh parenting (e.g., aggressive, abusive, highly conflictual), with few studies addressing IG transmission of positive parenting in non-clinical populations (e.g., parental monitoring, warmth and enjoyment, inductive discipline, ‘normative’ levels of conflict). Furthermore, evidence of sex differences in IG transmission of parenting is almost non-existing, with most studies historically focusing on mothers and not fathers, without differentiating between genetic, psychological and contextual factors that may confound IG transmission of parenting. Importantly, it remains unclear through which processes and/or mechanisms parenting is transmitted across generations and the role it plays in offspring mental health and development due to retrospective designs and lack of prospective longitudinal three-generational study on parenting and mental health that enable to infer causality. Understanding processes that underly continuity and stability of IG transmission of parenting (i.e., mediators) and factors that disrupt continuity and stability of IG transmission of parenting (i.e., moderators) is of crucial importance to preventive (e.g., enhancing positive parenting) and targeted intervention programs (e.g., disrupting negative parenting) to break the IG cycle of negative parenting and adverse offspring outcomes.

Although self-reported data on parenting captures parental perceptions and attitudes to parenting, it may be biased by parental mental health status and does not capture the nature and quality of family and parent-child interactions. Specifically, family interactions provide a fundamental context for offspring development. In two-parent families (irrespective of parental sex and gender), children experience dyadic and triadic interactions routinely. Family-systems perspective emphasises importance of family sub-systems, such as mother-child, father-child, parent-parent relationship and co-parenting, as developmentally formative in influencing offspring development. These interactional subsystems are interrelated exerting mutual effects, however, they are not captured by dyadic mother- and father-child interactions. Dyadic interactions provide important insights into individual patterns of parent-child interactions (within sub-systems), which are related yet distinct from interaction patterns within other family sub-systems, including parental relationship and co-parenting sub-systems. Emphasis on dyadic parent-child interactions only obscures important role that family-level interactions play in offspring development because accumulation of individual measures is not equivalent to the whole family measure and parental and child behaviours may not be organised in the same way across dyadic and triadic contexts. Furthermore, children have the capacity to engage in both dyadic and triadic interactions early in infancy, with both parental and child behaviours mutually affecting each other, suggesting the need to consider child interactive behaviours in the context of dyadic and triadic interactions. Despite developmental importance of triadic interactions, there is a distinct lack of studies examining both dyadic and triadic interactions and their impact on offspring developmental and mental health outcomes, particularly in the context of parental depression. This is a substantial limitation given growing evidence supporting the importance of triadic family interactions for offspring developmental and mental health outcomes, as well as important clinical implications. Qualitative meaning of the family interactions to parents is as important as behavioural manifestations, particularly in those families where parents experience mental health difficulties. However, it is rarely captured in research, constituting an important limitation as these meanings have important implications for the development of targeted interventions to improve parental and offspring mental health.