Researchers have uncovered another difference between the sexes: women get more, deeper wrinkles around their mouths than men do as they age.

And they have identified several reasons for the gender imbalance.

The research, which appears in the latest issue of the Aesthetic Surgery Journal, looked at both male and female cadavers, studying the skin around the upper lip.

They found several key differences between the sexes.

One of the major ones that lines are deeper in women is that women have fewer sweat glands around the mouth than men.