Now new research seems to have found the explanation. According Tomokhiro Kono, a professor at the University of Tokyo, the manager could be the father’s sperm.

Professor Kono recounts, in research published in, how the 13 mice in his laboratory created from two female eggs, and therefore with the genetic makeup of two mothers (mice bimaternos) live around 186 days longer than control mice born of the union of egg and sperm normal.

The odds of life of these animals is 600 to 700 days, which suggests that the sperm-free living through a 30% increase. To make matters worse, these animals have an immune system more active than their peers with parents.

Kono suspicion that the reasons for this difference in longevity could be related to a gene (Rasgrf1) of chromosome 9 associated with postnatal growth, and usually is inherited from the father.

“We have long known that women tend to live longer than men,” says Prof. Tomohiro Kono, and that these differences in longevity, related to gender, also occur with many other species of mammals. ”

“However, the reason for these differences so far was not clear and, in particular, was not known whether the longevity in mammals was controlled by the composition of the genome of only one or both parents.”

This is the first time it shows something like mammals and the study’s authors believe it could explain why females of many species live longer than those of the opposite sex.