Projecting sex imbalances at birth at global, regional and national levels from 2021 to 2100: scenario-based Bayesian probabilistic projections of the sex ratio at birth and missing female births based on 3.26 billion birth records
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    Age difference and changing marriage age can add to male surplus

    An additional factor of importance in the perception of a gender imbalance is the consequence of an age difference between partners (e.g. groom and bride) and the growth rate of the respective society. If, for example, there was a constant age difference of 5 years between (older) men and (younger) woman, and around 2% of annual population growth, leading to an increase of 10% in the number of births over each 5 years, that in its effect would just counterbalance a 10:9 sex imbalance (around 47.5% women to 52.5% men). In a shrinking society with a similar preference for younger women, the two effects would add and the imbalance in birth rates would feel even worse for men.

    The imbalance would ultimately affect the “market power” of the respective genders in partnerships and/or the “marriage market”. If women actually prefer a partner of similar age, and woman of one cohort can start to pursue that preference due to the “oversupply” of men, this would further enhance the marriage squeeze for men, as even more of the older bachelors would be left out while the women turn to the younger competitors of the older men. Certainly, in the advent of such transition, some men will overlook that effect and thus be left out unmarried once the patterns have changed.

    A gradual increase of the age of marriage may also trigger or enhance that effect: Young women (or their parents, to the extent they are participating in the choice of their daughters partner or life partner)...

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    Conflict of Interest:
    None declared.