Why women live longer than men?

Researchers have found a genetic clue of why women generally live longer than men.

The research, published in the journal Current Biology and conducted by Lancaster University in Britain reported that a set of DNA inherited only from the mother can be harmful to males and speed up male aging.

After carrying experiments with fruit flies, researchers said the results point to numerous mutations within mitochondrial DNA that affect how long males live, and the speed at which they age.

Mitochondrial DNA, which is found in many species including human, is inherited through the mother only. So there is no evolution pressure from the male side to sieve out those mutations that are just harmful to male, and the unaffected females will continue to pass on those mutations to their sons.

The accumulation of those mutations could eventually lead to the difference of longevity between male and female. That theory was named "Mother s Curse" by some researchers.

Generally women outlive men by about five to six years. By age 85 there are roughly six women to every four men and by age 100 the ration is more than two to one.