Testosterone may hold the key to the disparity in men and women's life spans, research on Korean eunuchs suggested Monday.
On average, females of mammalian species including humans have 10 per cent longer life spans.
Professor Min Kyung-jin of Inha University and professor Lee Cheol-koo of Korea University analysed the family records of 81 Joseon Dynasty eunuchs who lived between 1556 and 1919.
The records showed that the eunuchs lived on average 14 years longer than the ruling-class males of that period, and three of the 81 eunuchs lived to be over 100 years old.
The research showed that on average eunuchs lived to the age of 70, while the figure for ruling-class men ranged from 51 and 56 years of age.
While the lifespan-extending effect of castration has been proven in domesticated animals, this is the first time a similar relationship between longevity and castration has been shown in humans, the Ministry of Education, Science and Technology said.
Unlike eunuchs found in other cultures, those of Korea's Joseon Dynasty adopted other eunuchs and kept genealogical records, which allowed the research, Min said.