Men who have good-looking sons are themselves regarded as better-looking by women, according to a study (stock image pictured)

Men who have good-looking sons are themselves regarded as better-looking by women, according to a study.

A man’s ability to sire a handsome child is an instinctive sign that he has good-quality genes, making him appear more attractive than if he had an uglier child, the researchers suggest.

From an evolutionary perspective, women’s preference for certain traits in a man have emerged because they provide clues that he has the ability to pass on genes that will increase the survival or reproductive success of any children they produce.

Women like men with symmetrical faces, for example, because this suggests he has ‘good genes that may confer disease resistance and other genetic benefits to their offspring’, said the researchers.

‘Offspring attractiveness provides extra information about the genetic quality of the father,’ they added.

For the study, by the University of Trnava, Slovakia, the researchers showed 260 women photos of men who had previously been rated on their looks in a separate experiment.

The photos of the men were paired alongside photos of boys aged between 4 and 5 who had also previously been rated as an attractive or unattractive child.

The women were told that the boys were the men’s sons (though in reality they weren’t).

When the photos of the men were paired with an attractive ‘son’ the women tended to rate the man as more attractive, and when they were paired with an unattractive ‘son’ the men’s perceived attractiveness fell.

A man’s ability to sire a handsome child is an instinctive sign that he has good-quality genes, making him appear more attractive than if he had an uglier child, the researchers suggest (chromosomes pictured)

The findings don’t just apply to divorced or otherwise unattached fathers who are on the lookout for a new partner, but for those who are still in a relationship with the mother of their child, the researchers added.

Women may judge the attractiveness of their existing partner according to the beauty of the child they produce, the researchers suggested.

‘Evaluation of the perceived attractiveness of the male after mating continues, and the production of a facially less attractive son results in decreased attractiveness of the father,’ the researchers wrote in the journal Archives of Sexual Behaviour.