Oxidative stress and antioxidants could be the reason why some people are more attractive than others, a recent study has found.
Psychologists have discovered that men who were rated as the most physically attractive by women have the lowest levels of markers of oxidative stress.
"These findings have several important implications," the Independent quoted psychologist Dr Steven Gangestad, who led the study, as saying.
"They fit in with the idea that women evolved to find particular features attractive because those features are related to low levels of oxidative stress," he stated.
Researchers found that it is not a chosen trait but one that is inborn, and which has evolved over time as a way of distinguishing the virile from the weak.
As cells use oxygen to make energy, they can create free radicals. These are unstable molecules that can have chemical reactions with other molecules, causing the cell damage known as oxidative stress.
Free radicals can be kept in check by antioxidants, but if there is an overabundance of radicals, the resulting oxidative stress can damage DNA and tissue.
Oxidative stress is thought to be a major cause of mutations and to play a part in ageing and a host of diseases, including cancer.
The findings have been published in the journal Animal Behaviour.