To know and be known: the proportion of genetic similarity for liability for neuroticism in mother-child and mother-father dyads is associated with reported relationship quality

Aim: To explore the influence of genetic similarity for neuroticism in mother’s reported quality of relationship with her child and partner. Such understanding could provide insight into the role of genetic similarity in close relationships. Method: Molecular genetic data in 4,704 mothers, partners, and children in the Avon Longitudinal Study Parents And Children (ALSPAC) study were used to derive the proportion of genetic similarity between mother and child, as well as mother and partner, for genetic variants associated with neuroticism. The associations between genetic similarity scores and mothers’ reported enjoyment and conflict in the parenting relationship (child age 0-3) and her reported relationship with the partner were examined. Results: For a one standard deviation (SD) increase in similarity in mother and child genetic variants associated with neuroticism, there was a 0.15 SD point (95% CI=0.003 to 0.500, p=0.046) increase in maternal reported enjoyment in their relationship. This association was greater where mother and child were both in the top quartile for high neuroticism (standardised beta=0.29, 95% CI=0.56 to 0.02, p=0.034). Similar patterns of results emerged for similarity for genetic variants associated with neuroticism between mothers and partners, and the quality of the mother-partner relationship reported by the mother. Implications: These results highlight how phenotypic variation linked to genetic liability in one individual may be influenced by the genetic liability of those around them. In other words, parenting and intimate partner relationships were explained not by one or the other’s genetic score, but by their combination. The associations between genetic similarity and parental enjoyment were small and explain only a small proportion of the variance. Thus, other parental and child factors, both genetic and environmental, are important in explaining variance in parenting. Nonetheless, these exploratory findings present an intriguing mechanism by which combined genetic liability might influence family relationships.