The future of sperm: a biovariability framework for understanding global sperm count trends
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The future of sperm a biovariability framework for understanding global sperm count trends.pdf
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Author(s)
Boulicault, Marion
Perret, Meg
Galka, Jonathan
Borsa, Alex
Gompers, Annika
Reiches, Meredith
Richardson, Sarah
Date Issued
May 10, 2021
Journal
Human Fertility
Publisher
Taylor & Francis
Citation
Boulicault, M., Perret, M., Galka, J., Borsa, A., Gompers, A., Reiches, M., & Richardson, S. (2022). The future of sperm: a biovariability framework for understanding global sperm count trends. Human Fertility, 25(5), 888–902.
Version
Final published version
Abstract
The past 50 years have seen heated debate in the reproductive sciences about global trends in human sperm count. In 2017, Levine and colleagues published the largest and most methodologically rigorous meta-regression analysis to date and reported that average total sperm concentration among men from ‘Western’ countries has decreased by 59.3% since 1973, with no sign of halting. These results reverberated in the scientific community and in public discussions about men and masculinity in the modern world, in part because of scientists’ public-facing claims about the societal implications of the decline of male fertility. We find that existing research follows a set of implicit and explicit assumptions about how to measure and interpret sperm counts, which collectively form what we term the Sperm Count Decline hypothesis (SCD). Using the study by Levine and colleagues, we identify weaknesses and inconsistencies in the SCD, and propose an alternative framework to guide research on sperm count trends: the Sperm Count Biovariability hypothesis (SCB). SCB asserts that sperm count varies within a wide range, much of which can be considered non-pathological and species-typical. Knowledge about the relationship between individual and population sperm count and life-historical and ecological factors is critical to interpreting trends in average sperm counts and their relationships to health and fertility.
MIT Department
Massachusetts Institute of Technology. Department of Linguistics and Philosophy
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Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.1080/14647273.2021.1917778
