Human sex-ratio manipulation: Historical data from a german parish

Abstract

On the basis of demographic data of a parish in Schleswig-Holstein, characterized by a primarily rural economy, the thesis is developed that during the period investigated, i.e. from 1720 to 1869 A.D., the survival chances of newborns were influenced by differential parental investment. The (first-born) daughters of land-owning farmers were most affected by this intervention, i.e. as a result of less well being taken care of. This resulted in sex-linked infant mortality and therefore a manipulation of the sex ratio. The social undesirability of girls or the preference of, and hence the greater investment in boys by these farmers can be explained by two socio-economic factors that appear to determine the reproductive value of the children: (1) inheritance practices favouring male descendants, and (2) the proportion of marriage perspectives for the sons as opposed to the daughters being in favour of the boys, in contrast to other social classes. The classes of the parish without land property revealed a different pattern of demographic features. Here the irrelevance of inheritance conventions and the relatively good chances of marriage for the daughters (especially the relatively high chances of hypergamy for the daughters of the smallholders) in comparison with those of the sons led to partially reversing of social undesirability and sex-linked reproductive value. Indeed, among the non-possessing classes, the survival chances of the boys were the lowest, relative to their sisters, and those of the girls were the highest. This means that, here too, the operation of cost-benefit-oriented parental investment can be assumed to have been present in the society discussed.