A study of Korean genealogical records has revealed that palace eunuchs lived an average of 14 to 19 years longer than typical men from the same time period.

This finding is sure to spark some lively discussion between couples of all ages.

Eunuchs are castrated males. Throughout most of history, they've been favored as guards and servants in many areas of the Middle East and Asia. While some eunuchs lost their reproductive organs in accidents, others underwent castration as a way to get ahead in life. In Korea, castration was a way to gain entry to the palace.

The researchers attribute the longer life of eunuchs to the absence of male sex hormones. Some studies suggest that these hormones impair immune function and predispose men to cardiovascular disease.

The researchers looked at genealogical records of members of the Imperial court of the Korean Chosun dynasty, which lasted from 1392 to 1910 AD. Court membership conferred many privileges and was hereditary, so members of the court had a strong incentive to keep accurate genealogical records.

The 81 eunuchs whose life spans were found in the records lived an average of 70 years. The lifespans of nearly 2,600 members of three other families of similar social status ranged from 50.9 to 55.6 years for each family. So the eunuchs lived 14 to 19 years longer on average. Three of the eunuchs even lived to 100 or beyond, a rate at least 130 times higher than in men of today, though three is a pretty small sample of centenarians to base a comparison on.

Why did the eunuchs live longer? It can't be due to palace life, because most eunuchs lived outside the palace and spent time inside only when they were on duty. And it can't be attributed to avoidance of women, either. Korean eunuchs were allowed to marry and to continue their line by adopting castrated boys or normal girls.

The researchers attribute the longer life of eunuchs to the absence of male sex hormones. Some studies suggest that these hormones impair immune function and predispose men to cardiovascular disease. Eunuchs no longer produce these hormones.

Sometimes there really is no gain without pain.

It's well established that women live longer than men do. This study lends some credence to the idea that male sex hormones are at least partially to blame. The study authors quip: "For better health and longevity, stay away from stresses and learn what you can from women." Of course, men are perfectly free to do the opposite, learning what they can about stresses and avoiding the company of women altogether.

A letter describing the study appears in the September 25, 2012 issue of Current Biology.