Although many studies have shown that there are trade-offs between longevity and reproduction, whether such trade-offs exist in humans has been a matter of debate []. In many species, including humans, males live shorter than females, which could be due to the action of male sex hormones. Castration, which removes the source of male sex hormones, prolongs male lifespan in many animals, but this issue has been debated in humans []. To examine the effects of castration on longevity, we analyzed the lifespan of historical Korean eunuchs. Korean eunuchs preserved their lineage by adopting castrated boys. We studied the genealogy records of Korean eunuchs and determined the lifespan of 81 eunuchs. The average lifespan of eunuchs was 70.0 ± 1.76 years, which was 14.4–19.1 years longer than the lifespan of non-castrated men of similar socio-economic status. Our study supports the idea that male sex hormones decrease the lifespan of men.

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4 Roberts M.L.

Buchanan K.L.

Evan M.R. Testing the immune competence handicap hypothesis: a review of the evidence. 5 Schwarcz M.D.

Frishman W.H. Testosterone and coronary artery disease. 6 Drori D.

Folman Y. Environmental effects on longevity in the male rate: exercise, mating, castration and restricted feeding. 7 Hamilton J.B.

Mestler G.E. Mortality and survival: comparison of eunuchs with intact men and women in a mentally retarded population. 8 Nieschlag E.

Nieschlag S.

Behre H.M. Lifespan and testosterone. In many mammalian species, including humans, the lifespan of males is shorter than that of females. One explanation for this is that male sex hormones reduce the lifespan of men because of their antagonistic role in immune function []. Male sex hormones also predispose men to adverse cardiovascular events []. Therefore, male sex hormones could be responsible for the reduced lifespan of men. The effects of male sex hormones on lifespan have been examined by observing the effects of castration, which typically prolongs lifespan in animals [], but studies on its influence in humans have yielded limited and debatable findings. Castration prolonged the lifespan of mentally ill, institutionalized men [], whereas the lifespan of castrato singers was not markedly different from that of non-castrated singers [].

A eunuch is a castrated human male, and historically, eunuchs have been employed as guards and servants in harems across the Middle East and Asia. The Imperial court of the Korean Chosun Dynasty (1392–1910) also had eunuchs. Eunuchs of the Chosun Dynasty lived with privileges: Korean eunuchs were conferred with official ranks and were legally allowed to marry, a practice that was officially banned in the Chinese Empire. In addition, married couples were also entitled to have children by adopting castrated boys or normal girls. The boys lost their reproductive organs in accidents, or they underwent deliberate castration to gain access to the palace before becoming a teenager. Although the family of a eunuch was composed of non blood-related members, the bonding in these families is believed to have been as strong as that in traditional blood-related families.

9 Wilson J.D.

Roehrborn C. Long-term consequences of castration in men: lessons from the Skoptzy and the eunuchs of the Chinese and Ottoman courts. ) — a genealogy record of Korean eunuchs. To our knowledge, this is the only record of eunuch-family histories in the world. The Yang-Se-Gye-Bo is the genealogical record of eunuch families from the progenitor Deuk-Bu Yoon and was written in 1805 by Yoon-Muk Lee (thirteenth generation of the progenitor, 1741–1816). It describes birth and death dates, place of birth, rank in the Royal court, names of wives and adopted son(s), and direction for the burial location of the late eunuchs. The validity of the Yang-Se-Gye-Bo was confirmed by cross reference to the Annals of the Chosun Dynasty and Diary of the Royal Secretariat ( Several studies have described the long-term consequences of castration in eunuchs, but there have been no data on the lifespan of eunuchs []. We examined the lifespan of Korean eunuchs by analyzing the Yang-Se-Gye-Bo () — a genealogy record of Korean eunuchs. To our knowledge, this is the only record of eunuch-family histories in the world. The Yang-Se-Gye-Bo is the genealogical record of eunuch families from the progenitor Deuk-Bu Yoon and was written in 1805 by Yoon-Muk Lee (thirteenth generation of the progenitor, 1741–1816). It describes birth and death dates, place of birth, rank in the Royal court, names of wives and adopted son(s), and direction for the burial location of the late eunuchs. The validity of the Yang-Se-Gye-Bo was confirmed by cross reference to the Annals of the Chosun Dynasty and Diary of the Royal Secretariat ( Supplemental information ). The activities of many eunuchs are described in both records, which verify that they were alive at that time.

Figure 1 Lifespan of Korean eunuchs and normal men. Show full caption The lifespan of eunuchs and non-eunuchs displayed as box plots. The box encompasses the 25th–75th percentile of the data with the median shown as a solid horizontal line. The top and bottom lines indicate the maximum and minimum lifespan for each family, respectively. The Yang-Se-Gye-Bo contains the records of 385 eunuchs. From these records, the lifespans of 81 eunuchs could be identified. The average lifespan of this group was 70.0 ± 1.76 years (27–109 years; Figure 1 ). As lifespan is affected by genetic and socio-economic factors, we compared the lifespan of eunuchs with the lifespan of men from three non-eunuch families of similar social status, who lived during the same time periods ( Supplemental information ). The average lifespan of the non-eunuchs ranged from 50.9 to 55.6 years (age range: 15–100 years for the Mok, 13–95 years for the Shin, and 20–81 years for the Seo family), which was significantly less than the lifespan of the eunuchs ( Figure 1 ). Furthermore, the inter-quartile range for the eunuch group (19 years) was more compact than those of the Mok, Shin and Seo families (26, 24 and 23 years, respectively). Interestingly, out of the 81 eunuchs, three were centenarians, aged 100, 101, and 109 years. The current incidence of centenarians is one per 3,500 in Japan and per 4,400 in the United States. Thus, the incidence of centenarians among Korean eunuchs is at least 130 times higher than that of present-day developed countries. Can the different living circumstances of eunuchs be attributed to the lifespan difference? Except for a few eunuchs, most lived outside the palace and spent time inside the palace only when they were on duty. Notably, the average lifespan of kings and male royal family members, who spent their whole lives inside the palace, was 47.0 ± 3.21 and 45.0 ± 2.79 years, respectively.