A new research has revealed that couples who are attractive are more likely to give birth to daughters, which could lead to the world’s women being better looking than men.
Researchers have established that very attractive people are 36 per cent more likely to have daughters than sons.
The report, from the London School of Economics, may provide an insight into the biological forces that lead the most striking people to produce first-born daughters.
It postulates that differing "evolutionary strategies" lead parents to produce the sex that would most benefit from their own characteristics.
So while the children of aggressive, scientific parents tend to be boys, who can outwit their competitors when it comes to finding a mate, the children of beautiful, empathic parents tend to be girls, who can take their pick from the gene pool and then hang on to their man.
"These may be stereotypes but they are also fact," Dr Satoshi Kanazawa, the evolutionary psychologist who led the research, was quoted by The Telegraph, as saying.
"We have shown that beautiful parents have more daughters than ugly parents because physical attractiveness is heritable and because daughters benefit from this more than sons."
The findings are not short of famous examples, including Brad Pitt and Angelina Jolie, the actors who named their daughter Shiloh Nouvel and can now claim a family waxwork at Madame Tussaud's and Grace Kelly, whose firstborn with Prince Rainier of Monaco was the beautiful Princess Caroline.
The research, published in the Journal of Theoretical Biology, was carried out using young Americans, who were analysed by height, weight and apparent age - factors that can be used to judge basic attraction levels without subjectivity. Only first-born children were included.