Finding a beautiful wife could be about to get easier.
According to the latest research, beautiful parents are a third more likely to have daughters than sons.
As time goes on, the beauty gap between men and women is expected to grow, the findings suggest.
In theory, women should go on becoming more attractive than men.
Researchers demonstrated that beautiful people are 36 per cent more likely to have a daughter than a son as their first born child.
The discovery supports the evolutionary theory that parents tend to produce children who benefit from their own attributes.
Selection pressure means that when parents have traits they can pass on that are better for boys than for girls, they are more likely to have boys.
Such traits include large size, strength and aggression, which might help a man compete for mates.
On the other hand parents with heritable traits that are more advantageous to girls are more likely to have daughters.
Study leader Dr Satoshi Kanazawa, an evolutionary psychologist at the London School of Economics, said: "Physical attractiveness is good for both men and women, but it is much better for women than for men. So physically attractive parents bias their offspring sex ratio to have more daughters."
Dr Kanazawa based his conclusions on data from 3,000 Americans taking part in an investigation called the National Longitudinal Study of Adolescent Health. Participants were assessed for factors that provide an objective measurement of attractiveness, such as symmetry and secondary sexual characteristics.
He said the idea that "beauty is in the eye of the beholder" was a myth debunked by psychologists 20 years ago.
"Physical attractiveness is an objective, quantifiable trait of a person just like height or weight," he said.
"There is now a computer program which can measure someone's physical attractiveness down to a decimal point. Physical attractiveness is rooted in the geometric concept of symmetry, mathematical concept of averageness, and biological concept of secondary sexual characteristics."
People from all societies agree on who is beautiful and who is ugly, he stressed. And infants can tell the beautiful and ugly apart within a few weeks of being born.
Previous research by Dr Kanazawa has shown that scientists, mathematicians and engineers who have systematic "male brains" are more likely to have sons than daughters.
The growing beauty gap: Mike Jagger and Bianca after their wedding in St Tropez. Bianca with the Jaggers' daughter Jade and (right) the golden oldie pop star