Child volunteers in a women's paramilitary organization in World War II have accelerated reproductive schedules

Sex, age, and family structure influence dispersal behaviour after a forced migration

Dispersal does not only mean moving from one environment to another, but can also refer to shifting from one social group to another. Individual characteristics such as sex, age and family structure might influence an individual's propensity to disperse. In this study, we use a unique dataset of an evacuated World War II Finnish population, to test how sex, age, number of siblings and birth order influence an individual's dispersal away from their own social group at a time when society was rapidly changing. We found that young women dispersed more than young men, but the difference decreased with age. This suggests that young men might benefit more from staying near a familiar social group, whereas young women could benefit more from moving elsewhere to find work or spouses. We also found that having more younger brothers increased the propensity for firstborns to disperse more than for laterborns, indicating that younger brothers might pressure firstborn individuals into leaving. However, sisters did not have the same effect as brothers. Overall, the results show that individual characteristics are important in understanding dispersal behaviour, but environmental properties such as social structure and the period of flux after World War II might upend the standard predictions concerning residence and dispersal. Social media summary: Individual characteristics influence dispersal away from social group after a forced migration in a Finnish population.

Social and Biological Transgenerational Underpinnings of Adolescent Pregnancy

Adolescent pregnancy (occurring < age 20) is considered a public health problem that creates and perpetuates inequities, affecting not only women, but societies as a whole globally. The efficacy of current approaches to reduce its prevalence is limited. Most existing interventions focus on outcomes without identifying or addressing upstream social and biological causes. Current rhetoric revolves around the need to change girls' individual behaviours during adolescence and puberty. Yet, emerging evidence suggests risk for adolescent pregnancy may be influenced by exposures taking place much earlier during development, starting as early as gametogenesis. Furthermore, pregnancy risks are determined by complex interactions between socio-structural and ecological factors including housing and food security, family structure, and gender-based power dynamics. To explore these interactions, we merge three complimentary theoretical frameworks: "Eco-Social", "Life History" and "Developmental Origins of Health and Disease". We use our new lens to discuss social and biological determinants of two key developmental milestones associated with age at first birth: age at girls' first menstrual bleed (menarche) and age at first sexual intercourse (coitarche). Our review of the literature suggests that promoting stable and safe environments starting at conception (including improving economic and social equity, in addition to gender-based power dynamics) is paramount to effectively curbing adolescent pregnancy rates. Adolescent pregnancy exacerbates and perpetuates social inequities within and across generations. As such, reducing it should be considered a key priority for public health and social change agenda.

The Impact of Stress Within and Across Generations: Neuroscientific and Epigenetic Considerations

The impact of stress and trauma on biological systems in humans can be substantial. They can result in epigenetic changes, accelerated brain development and sexual maturation, and predisposition to psychopathology. Such modifications may be accompanied by behavioral, emotional, and cognitive overtones during one's lifetime. Exposure during sensitive periods of neural development may lead to long-lasting effects that may not be affected by subsequent environmental interventions. The cumulative effects of life stressors in an individual may affect offspring's methylome makeup and epigenetic clocks, neurohormonal modulation and stress reactivity, and physiological and reproductive development. While offspring may suffer deleterious effects from parental stress and their own early-life adversity, these factors may also confer traits that prove beneficial and enhance fitness to their own environment. This article synthesizes the data on how stress shapes biological and behavioral dimensions, drawing from preclinical and human models. Advances in this field of knowledge should potentially allow for an improved understanding of how interventions may be increasingly tailored according to individual biomarkers and developmental history.