Parental Investment by Birth Fathers and Stepfathers

Abstract

This study investigates the determinants of paternal investment by birth fathers and stepfathers. Inclusive fitness theory predicts higher parental investment in birth children than stepchildren, and this has consistently been found in previous studies. Here we investigate whether paternal investment varies with childhood co-residence duration and differs between stepfathers and divorced birth fathers by comparing the investment of (1) stepfathers, (2) birth fathers who are separated from the child’s mother, and (3) birth fathers who still are in a relationship with her. Path analysis was conducted using cross-sectional data from adolescents and younger adults (aged 17–19, 27–29, and 37–39 years) from the German Family Panel (pairfam), collected in 2010–2011 (n = 8326). As proxies of paternal investment, we used financial and practical help, emotional support, intimacy, and emotional closeness, as reported by the children. We found that birth fathers who were still in a relationship with the mother invested the most, and stepfathers invested the least. Furthermore, the investment of both separated fathers and stepfathers increased with the duration of co-residence with the child. However, in the case of financial help and intimacy, the effect of childhood co-residence duration was stronger in stepfathers than in separated fathers. Our findings support inclusive fitness theory and mating effort theory in explaining social behavior and family dynamics in this population. Furthermore, social environment, such as childhood co-residence was associated with paternal investment.

Step-grandparental investment: role of childhood co-residence with grandchild’s parent

“…In line with inclusive fitness theory , stepparents are consistently found to invest less in children compared to biological parents (e.g., Anderson 2011, Arat et al, 2022Pettay et al, 2023). This has been referred to as the "step-gap" (e.g., Becker et al, 2013;Delongis & Preece, 2002) and "Cinderella effect" (e.g., Daly & Perry, 2021) in prior literature.…”

The role of mating effort and co-residence history in step-grandparental investment

“…The age of the child at the onset of step parenthood is also acknowledged as a potential factor influencing step-relationships (e.g. Hornstra et al, 2020 ; Kalmijn, 2013 ; Pettay et al, 2023 ). In the present study, we were unable to identify a connection between childhood co-residence and step-grandparental investment.…”

“…In line with inclusive fitness theory (Hamilton, 1964), step-parents are consistently found to invest less in children compared with biological parents (e.g. Anderson, 2011;Arat et al, 2022;Pettay et al, 2023). This has been referred to as the 'step-gap' (e.g.…”

“…Daly & Perry, 2021 ) in prior literature. Step-parenting is not a novelty among humans, and the relationship between step-parents and step-children can extend beyond childhood (Kalmijn, 2013 ; Becker et al, 2013 ; Pettay et al, 2023 ). The origin of step-parental investment, i.e.…”

“…For instance, an increased co-residence duration in childhood is associated with increased investment by step-fathers and fathers who had separated from the mother (e.g. Kalmijn, 2013 ; Pettay et al, 2023 ) and half-siblings (e.g. Tanskanen & Danielsbacka, 2019 ; Tanskanen et al, 2021 ; Lieberman et al, 2007 ; Steinbach & Hank, 2018 ).…”