Rumors of declining testosterone and sperm count in men have been a staple of Manosphere ideology and political concerns about lower birth-rates. A new meta-analysis of scholarly articles published since 1970 concludes that there is no evidence of diminished male fertility or sperm count during this period. This directly contradicts the findings of a 2023 meta-analysis which found that there was indeed a significant decline during a comparable period.
Other scholars have suggested serious limitations in the available methodologies for measurement that make it difficult to compare studies
