On the masculinization of population: The contribution of demographic development - A look at sex ratios in Sweden over 250 years

Abstract

BACKGROUND Almost everywhere, women live longer than men, but the world population includes increasingly more men than women. This fact is observed not only in populations where gender-based discrimination is practised, but also in developed countries like Sweden. OBJECTIVE Whereas discrimination against female infants and women is usually given as an explanation for this paradox, demographic development (through improved survival) also plays a role. This study examines the largely unnoticed role of demographic development in the masculinization of population, taking the case of Sweden. METHODS Using high-quality data from the Human Mortality Database for Sweden over the last 250 years, changes in the sex ratio at various ages are described and linked to the continuing survival gains achieved over the mortality transition. RESULTS Thanks to the reduction of secular mortality in Sweden, the natural sex imbalance observed at birth has been progressively prolonged later in life, and the age at which women outnumber men has been postponed to older ages. Similar developments are found in Norway and Denmark. CONCLUSIONS The general decline of mortality is one of humanity's biggest achievements, but the accompanying change in age- and sex-specific survival patterns, coupled with the natural sex imbalance at birth, influences the age and sex composition of a population and, therefore, the sex ratio at successive ages. In a world where each new generation can expect to enjoy a longer life than the previous one, an increasing number of men can also be expected. CONTRIBUTION The role of demographic development in the masculinization of population has remained largely unnoticed so far.