Introduction

The observation that eunuchs, or males who have been castrated, tend to live longer than their intact counterparts has been noted since ancient times. This phenomenon has intrigued scientists and historians alike, as there have been few adequate explanations. Recent studies, however, have delved deeper into the biological mechanisms that may underlie this intriguing observation.

Historical Observations

The phenomenon of castration leading to increased longevity was first recorded in ancient Greece. As early as Aristotle, there have been references to eunuchs living longer lives. Despite this historical observation, a scientific explanation remained elusive until more recent studies.

Modern Scientific Studies

Hamilton and Mestler's Study (1969)

One of the earliest and most notable studies addressing this question was conducted by Hamilton and Mestler in 1969. They examined a group of eunuchs who had been castrated for eugenic purposes in Kansas. Comparing these eunuchs to individuals matched by age, social status, and other criteria, they found that boys castrated before puberty lived an average of 14 years longer than those who had not been castrated. For individuals castrated between the ages of 15 and 19, the additional lifespan was about 8 years, with the advantage gradually decreasing with later ages of castration. Male eunuchs also lived longer than females in the same institutions. This study provided compelling evidence that castration could extend lifespan.

Nico Nagelkerke's Analysis (2012)

Nico Nagelkerke, a respected Dutch biostatistician and infectious disease epidemiologist, analyzed the data from Hamilton and Mestler's study and concluded that the findings supported the hypothesis of extended lifespan due to castration.

Lee, Koo, and Park's Study (2012)

Lee, Koo, and Park conducted a study on Korean eunuchs from the Chosun Dynasty, where there was solid data on their dates of birth, castration, and death. They found an average increase in lifespan of 19 years, with the percentage of eunuchs living to 100 years being at least 130 times higher than that for intact men in the developed world today.

Recent Research Findings

The most recent and promising research in this field was conducted by a team of eighteen medical researchers from universities in the United States and New Zealand. They studied changes in DNA in sheep that had been castrated and found cellular mechanisms that delayed aging, providing an explanation for why castrated males live longer than non-castrated males or females.

Impact on Cellular Aging

The researchers found that testosterone, a potent androgen, and estrogens, which are weaker in effect, degrade cellular DNA over time, leading to aging and death. This degradation process is slower in castrated individuals, contributing to their extended lifespan. Their research, although conducted on sheep, suggests that similar mechanisms might be at play in humans.

The article by Sugrue et al. (2021) titled 'Castration delays epigenetic aging and feminizes DNA methylation at androgen-regulated loci' is available as an open-access source. You can access it via the DOI link and download the PDF.

Conclusion

While we now have substantial evidence suggesting that castration can extend longevity, further research is needed to confirm these findings in humans. The biological mechanisms behind this phenomenon remain a focus of ongoing investigation.

References

Hamilton, J. B., Mestler, G. E. (1969). Mortality and survival: Comparison of eunuchs with intact men and women in a mentally retarded population. Journal of Gerontology, 24(4), 395-411. Lee, K.-J., Koo, C.-K., Park, H.-N. (2012). The lifespan of Korean eunuchs. Current Biology, 22(18), R792. Nagelkerke, N. J. D. (2012). Courtesans and consumption: How sexually transmitted infections drive tuberculosis epidemics. Uitgeverij Eburon. Sugrue, V. J., et al. (2021). Castration delays epigenetic aging and feminizes DNA methylation at androgen-regulated loci. eLife.