| Abstrakt: |
Background: Consistent across cultures and throughout time is the male preference for younger females. Given its prevalence, the mate choice theory proposes that age–disparate relationships may have contributed to the evolution of maternal mortality and menopause. Objectives: The objective is to document evidence for age disparity in marriage from past and present populations and evaluate their relevance to maternal mortality and menopause. Design: Cross-sectional data were collected from various regions and time points, ranging from the Roman era to the current decade. Methods: To analyze both the age disparity in marriage and age at marriage, data were collected from Ancestry.ca for Quebec, Massachusetts, India, South Africa, and England and Wales. Additional data were taken from the United Nations as a more recent and comprehensive source. To analyze the relationships between age disparity in marriage and different social factors, data on gross domestic product, maternal mortality rates, fertility, primary school enrollment, child marriage rates, and percentage of women in the total labor force were collected from the World Health Organization, World Bank, and United Nations International Children's Emergency Fund. Results: The results showed that males were significantly older than females at first marriage in all populations and time frames sampled, supporting the assumption underlying the mate choice theory. Maternal mortality rates were strongly associated with age–disparate relationships, increasing by 275 per 100,000 live births for each additional year in the age disparity. Conclusion: The results from this study provide support for the assumption underlying the mate choice theory of maternal mortality and menopause. Plain language summary: Changing patterns of global age disparity in marriage provide support for the mate choice theory of menopause, raising the possibility of a gradual shift in delayed reproduction and delayed menopause. Living things have inherent capacity to survive and reproduce until they die, with one exception: humans. Women go through menopause while men remain fertile. Among the many explanations offered for the origin of menopause, grandmother hypothesis is the leading one. Being too old to reproduce, it is argued, grandmothers stop reproducing and make up for the loss of fitness through helping (grand mothering) their grand offspring. There are two problems with this theory: first, grand mothering and menopause need not be connected, and second, grandmothers cannot be simultaneously too old to reproduce and not too old to be able to gather resources to make up for their loss of fitness. We proposed a mate choice theory of menopause which posits that human mating system is non-random, that is, males have preference for younger females, depriving older females from reproduction and allowing deleterious fertility mutations to accumulate giving rise to menopause. Male preference for younger females is consistent across cultures and dominates all social relations affecting mate choice including monogamy, serial monogamy, widowers remarrying, polygamy, harem, and others. In this study, we wanted to test if male preference for younger females has been widespread through time. We collected data on age disparity in marriage from past and present populations, from Roman era to the current decade, and evaluated their relevance to the origin of maternal mortality and menopause. The results showed that males were significantly older than females at first marriage in all populations and time frames sampled, supporting the assumption underlying the mate choice theory of menopause. Maternal mortality rates were strongly associated with age–disparate relationships, increasing by 275 per 100,000 live births for each additional year in the age disparity. Through repeated cycles of widowers marring younger women, maternal mortality would have functioned as a reinforcer of the origin of menopause. [ABSTRACT FROM AUTHOR] |
