Did the Sex Ratio at Birth Reflect Social and Economic Inequalities? The Pilot Study from the Poznań Province, 1875–1913

The goal of this study was to examine whether and to what extent sex ratio values at birth may have reflected social and economic inequalities in the Province of Poznań (German: Provinz Posen) in the last decades of the 1800s and early 1900s. It was assumed that maternal economic, social and emotional well-being differed according to the size of the place of residence (Poznań / town / village) and her marital status (married / unmarried). In the population of the Province, urban areas (e.g., Poznań) and single motherhood were the predictors increasing the chance that the proportion of boys to girls at birth would decline below the biological norm. These factors could affect women during pregnancy through biological (physiological) mechanisms induced by adverse economic conditions (poverty, poor housing conditions, physical effort related to work and spatial mobility) and psychological stress (lack of social approval and support, social instability, occurrence of stigmatization, etc.). It is worth noting, however, that the variability of sex ratio values at birth could also be due to other factors, not identified (captured) in this paper.