Do academic ability and social background influence each other in shaping educational attainment? The case of the transition to secondary education in Germany.

Studies examining the interplay between children's academic ability and parental background are rare, and their findings are mixed and inconclusive. This paper addresses possible reinforcing or compensating relationships between child characteristics and parental social background in their influence on the transition to upper secondary education, the most important transition in the German school system. We use the German TwinLife data for genetically informed analyses and include comprehensive information on parental background as well as child cognitive ability and personality. We find no evidence for a significant influence of reinforcing or compensatory interactions in addition to the strong additive effects of child and parental characteristics. The ACE decomposition with covariates shows an almost equal influence of genetic variation and shared environments. However, indicators of child academic ability and parental background contribute only a little to explaining both contributions. Interestingly, the influence of child characteristics on enrollment in upper secondary school works mainly through environmental rather than genetic effects.

Is there something special about twin families? A comparison of parenting styles in twin and non-twin families.

Twin comparisons offer a powerful quasi-experimental design to study the impact of the family of origin on children's life chances. Yet, there are concerns about the generalizability of results obtained from twin studies because twin families are structurally different and twins have a genetic resemblance. We examine these concerns by comparing mothers' reports on their parenting styles for twin and non-twin children between twin and non-twin families, as well as within twin families. We use two German studies for our comparisons: TwinLife and pairfam. Our results demonstrate that twins receive more differential treatment and more emotional warmth than non-twins; however, these differences are largely accounted for by age differences between children. Overall, our results indicate that results on parenting obtained from twin studies can be generalized to non-twin families.

The German Twin Family Panel (TwinLife).

The German Twin Family Panel (TwinLife) is a German longitudinal study of monozygotic and dizygotic same-sex twin pairs and their families that was designed to investigate the development of social inequalities over the life course. The study covers an observation period from approximately 2014 to 2023. The target population of the sample are reared-together twins of four different age cohorts that were born in 2009/2010 (cohort 1), in 2003/2004 (cohort 2), in 1997/1998 (cohort 3) and between 1990 and 1993 (cohort 4). In the first wave, the study included data on 4097 twin families. Families were recruited in all parts of Germany so that the sample comprises the whole range of the educational, occupational and income structure. As of 2019, two face-to-face, at-home interviews and two telephone interviews have been conducted. Data from the first home and telephone interviews are already available free of charge as a scientific use-file from the GESIS data archive. This report aims to provide an overview of the study sample and design as well as constructs that are unique in TwinLife in comparison with previous twin studies - such as an assessment of cognitive abilities or information based on the children's medical records and report cards. In addition, major findings based on the data already released are displayed, and future directions of the study are presented and discussed.

Family Systems and Fertility Intentions: Exploring the Pathways of Influence.

Family systems, as normative frameworks in which family processes unfold, are believed to exert a major influence on fertility. While a number of studies have addressed family system effects on family size and the timing of births, the question of how family systems influence fertility intentions has remained largely unexplored. Because fertility intentions are often not realized, studying the pathways through which these intentions are framed warrants further attention. Addressing this research gap, this paper explores the pathways of influence between family systems and people's intentions to start or to extend their family in the framework of the theory of planned Behaviour. We use a path analysis to analyse data from the Generations and Gender Survey (GGS) on fertility intentions of 28,988 individuals from nine European countries that considerably vary in family systems. Regional indicators of family systems were constructed on the basis the Survey of Health, Aging and Retirement in Europe (SHARE) and incorporated in the analytical sample. The results demonstrate an important link between family systems and fertility intentions. Family systems frame people's intentions by influencing their attitudes towards children and their ideas about existing norms regarding fertility. This influence works partly through affecting household size and partly through influencing people's ideas about the requirements for having children. Family system effects vary between intentions to start and to extend a family. While nearness to kin decreased positive attitudes towards having children of childless respondents, having kin nearby had the opposite effect for those that were already parents.

Does parental separation moderate the heritability of health risk behavior among adolescents?

Social influences on adolescents' health risk behavior are well documented, but little is known about the interaction of parental separation with genetic sensitivities. Using data from a German sample of 1762 twins, this study examines whether family living arrangements moderate the influence of genetic predispositions on health risk behavior. Derived from variance decomposition moderator models, three key findings emerge. Firstly, genetic contributions to drug use are significantly higher in single-mother families, indicating an amplified heritability potentially resulting from triggered genetic sensitivities or challenges in preventing genetic risks from unfolding. Secondly, unique environmental factors have a greater impact on drug use in single-mother families. Lastly, no heritability differences are found in smoking and excessive alcohol consumption between family types. These findings provide novel evidence of increased importance of genetic influences on drug use in single-mother families, shedding light on gene-environment interactions, and informing policy interventions that support vulnerable family arrangements.

Genetic and environmental contributions to the subjective burden of social isolation during the COVID-19 pandemic.

BACKGROUND: Feelings of loneliness and the burden of social isolation were among the most striking consequences of widespread containment measures, such as "social distancing", during the COVID-19 pandemic. Because of the potential impact on people's health, there has been increased interest in understanding the mechanisms and factors that contributed to feelings of loneliness and the burdens of social isolation. However, in this context, genetic predisposition has been largely ignored as an important factor. This is problematic because some of the phenotypic associations observed to date may in fact be genetic. The aim of this study is, therefore, to examine the genetic and environmental contributions to the burden of social isolation at two time points during the pandemic. In addition, we examine whether risk factors identified in previous studies explain genetic or environmental contributions to the burden of social isolation. METHODS: The present study is based on a genetically sensitive design using data from the TwinLife panel study, which surveyed a large sample of adolescent and young adult twins during the first (N = 798) and the second (N = 2520) lockdown in Germany. RESULTS: We find no substantive differences in genetic and environmental contributions to social isolation burden over the course of the pandemic. However, we find the determinants highlighted as important in previous studies can explain only a small proportion of the observed variance in the burden of social isolation and mainly explained genetic contributions. CONCLUSIONS: While some of the observed associations appear to be genetic, our findings underscore the need for further research, as the causes of individual differences in burden of social isolation remain unclear.