Cutting time short or long? Castration, developmental timing, and longevity in imperial China.

Tang dynasty eunuchs had a modest but statistically significant survival advantage over non-castrated bureaucrats.

• The abstract reports a difference of +3.02 years in age at death (p = 0.005).
• Hypothesis 1 compared age at death between eunuchs and bureaucrats within each dynasty.
• Analyses used bootstrapped regression models controlling for birth year.
• Data came from biographical records of eunuchs and non-castrated bureaucrats from the Tang dynasty (618-907 CE).

No significant difference in age at death between eunuchs and bureaucrats was observed in the Ming dynasty sample.

• The Ming dynasty period covered 1368-1644 CE.
• The same bootstrapped regression approach controlling for birth year was applied within the Ming dynasty.
• The abstract states that no significant difference was observed in the Ming sample.

Earlier court entry, used as a proxy for earlier age at castration, did not predict greater longevity among Ming eunuchs.

• Hypothesis 2 analysed a subset of 160 Ming eunuchs with recorded age at court entry.
• Both linear regression and puberty-threshold models were used.
• The abstract reports that earlier court entry did not predict greater longevity in either model.
• Age at court entry served as a proxy for age at castration, not a direct measure.

The author concludes that the survival effects of castration in humans appear modest and context-dependent rather than uniformly beneficial.

• The effects were described as shaped by broader biosocial and mortality conditions.
• The study was framed within life-history theory predicting a reproduction-longevity trade-off.
• Prior evidence from human populations on castration extending male lifespan was described as limited.