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Objectives: The secondary sex ratio (i.e., the ratio of male to female live births; hereafter referred to as the SSR) falls in populations encountering ambient stressors. Much theory and some empirical work indicates that males born to low SSR cohorts may be "positively selected" in that excess culling in utero may correspond with greater than expected survival among live-born males in that cohort. We extend prior work by testing, in historical Utah, whether the SSR varies positively with male mortality at pre-reproductive ages., Methods: This study uses detailed records from the Utah Population Database to focus on Utahns born 1850-1940. We use rigorous time-series methods, which control for strong secular declines in mortality as well as ambient perturbations shared equally among males and females, to investigate the male culling inference., Results: We observe a positive relation between the SSR and male mortality during youth (i.e., 5 to < 20 years; p < 0.05) but not in infancy or early childhood., Conclusions: In this historical population, the SSR appears to gauge hardiness of surviving male cohorts. However, whether the high fertility and/or family structure context of Latter-day Saints in historical Utah explains the age-specific pattern of male mortality warrants further scrutiny., (© 2024 Wiley Periodicals LLC.)

Evolutionary theory, when coupled with research from epidemiology, demography, and population endocrinology, suggests that contracting economies affect the fitness and health of human populations via natural selection in utero. We know, for example, that fetal death increases more among males than females when the economy unexpectedly contracts; that unexpected economic contraction predicts low secondary sex ratios; and that males from low sex ratio birth cohorts live, on average, longer than those from high sex ratio cohorts. We also know that low levels of human chorionic gonadotropin (i.e., hCG) measured in the serum of pregnant women predict fetal death. We do not, however, know whether male survivors of conception cohorts subjected to contracting economies exhibit, as theory predicts, higher hCG than those from other cohorts. We show, in 71 monthly conception cohorts including nearly two million California births, that they do. We thereby add to the literature suggesting that the economy, a phenomenon over which we collectively exercise at least some control, affects population health. Our findings imply that the effect arises via natural selection - a mechanism we largely ignore when attempting to explain, or alter, how collective choice affects our biology. [ABSTRACT FROM AUTHOR]

Background: Theory suggests that natural selection conserved reactivity in part because highly reactive women spontaneously abort less fit conceptuses, particularly small males. Other literature argues that high reactivity manifests clinically as anxiety disorders. If true, births to women diagnosed with anxiety disorders should exhibit a low secondary sex ratio (i.e. ratio of male to female births). We explored whether births to women diagnosed with anxiety disorders exhibit a lower sex ratio than births to women diagnosed with other psychiatric disorders, or to women without mental health diagnoses.Methods: We performed a case-control comparison of the secondary sex ratios among groups of women categorized by mental health diagnosis using birth records linked to data from California County Mental Health system records. We compared sex ratios among 5994 deliveries to mothers diagnosed with anxiety disorders, 23 443 deliveries to mothers diagnosed with other psychiatric disorders and 1 099 198 'comparison' births.Results: Although comparison births exhibited a higher sex ratio than births to women diagnosed with anxiety disorders or with other diagnoses, differences were not statistically significant. Births to African American women diagnosed with anxiety disorders, however, exhibited sex ratios significantly lower than comparison births among African Americans (OR = 0.89, P = 0.038) or births to African American women with other mental health diagnoses (OR = 0.88, P = 0.042).Conclusions: We found that infants born to African American women diagnosed with anxiety disorders exhibited a significantly lower secondary sex ratio than reference groups. We urge confirmatory tests of our findings and discuss implications of the reactivity/anxiety hypothesis for psychiatry, obstetrics and public health. [ABSTRACT FROM AUTHOR]