Australian scientists have discovered why the average life expectancy of men is less than that of women. The researchers wanted to test the hypothesis that in heterogametic individuals (males with a set of XY chromosomes), the Y chromosome may protect them less from harmful genes.

To confirm this position, experts analyzed the available literature on sex chromosomes and found that the same pattern existed among mammals, birds, reptiles, fish, amphibians and insects: the heterogamous sex (male) died before homogamous (female).

According to Biology Letters, the scientists concluded, based on observations, that the Y chromosome cannot “overcome” the X chromosome, carrying harmful mutations that could expose the body to various threats.

At the same time, there is no such problem in homogamous chromosomes (XX). One healthy X chromosome can replace another. Thus, harmful genes are not expressed and life expectancy increases.