"If a mitochondrial mutation pops up that is benign in females, or a mutation pops up that is beneficial to females, this mutation will slip through the gates of natural selection and go through to the next generation," said study researcher Damian Dowling, an evolutionary biologist at Monash Univeristy in Australia.

The result: a load of mutations that don't harm females, but add up to a shorter life span for males.

Mother's Curse

Dowling and his colleague tested this idea - dubbed "Mother's Curse" - in fruit flies (Drosophila melanogaster). They took flies with standardized nuclear genomes, meaning all had the same cellular DNA, and inserted mitochondrial DNA from 13 different fruit-fly populations around the world. [Global Life Expectancy (Infographic)]

"The only genetic difference across the strains of flies lay in the origin of the mitochondria," Dowling told LiveScience.