The Agricultural Endocrine-Disruption Cycle Hypothesis: Monoculture Agriculture, Microbial Monoculture, and the Post-Neolithic Y-Chromosome Bottleneck

Abstract

The post-Neolithic Y-chromosome bottleneck, a sharp reduction in male-line genetic diversity approximately 5,000–7,000 years ago, remains incompletely explained by existing sociocultural models.

This paper proposes that the agricultural transition created a novel endocrine-disrupting environment through three simultaneous changes: (i) increased reliance on phytoestrogen-containing staple crops; (ii) chronic exposure to potent mycoestrogens (zearalenone) and ergot alkaloids from fungal contamination of stored grains; and (iii) reduced gut microbial diversity that altered host capacity to metabolize and clear endocrine-active compounds. Drawing on developmental endocrinology, paleomicrobiomics, and paleometabolomics, the framework argues that persistent endocrine disruption during critical fetal developmental windows contributed to gradual reductions in male reproductive fitness.

The hypothesis generates predictions distinguishable from both the patrilineal competition model (Zeng et al. 2018) and the peaceful demographic drift model (Guyon et al. 2024), particularly regarding correlations between grain storage infrastructure, agricultural monoculture, mycoestrogen exposure, and bottleneck severity independent of social stratification. While the argument is inferential and intended primarily as a source of testable predictions for future interdisciplinary research, it identifies specific empirical tests that can constrain or falsify the proposed mechanism, such as targeted paleometabolomic screening of ancient dental calculus.