Married brothers true or not?
Scientists find mathematical formula for the perfect wife
A bride should be five years younger than her groom, should come from the same cultural background, and be the more intelligent of the pair if couples are to have a successful marriage, scientists have announced.
Sticking to the formula would increase a couple's chances of a long and happy marriage by a fifth, the team from the Geneva School of Business found.
One couple that the formula appears to fit is the Queen and the Duke of Edinburgh.
At 83, Her Majesty is four years, 10-and-a-half month younger than the Duke.
They certainly share the same sort of background, even if the foreign-born Duke - a member of the Greek and Danish royal families by birth - had to become a naturalised British subject before their marriage.
As to their respective intelligence, that would not be for one to speculate.
However, it would be fair to say that the Queen's natural sense of diplomacy has shone through countless times over the decades, matched on some occasions only by the Duke's seemingly innate ability to offend.
Their marriage has now seen off the slings and arrows of outrageous fortune for more than six decades, since they wed at Westminster Abbey in November 1947.
The academic study, published in the European Journal of Operational Research looked at 1,074 couples aged between 19 and 75 years, to find which social factors were most important to a long and happy relationship.
Besides the man being five years older than his bride, and that his bride should share the same heritage, they concluded that a wife should be at least 27 per cent more intelligent than her husband. She should also hold a degree, while he should not.
Perhaps unsurprisingly, the academics found that marrying a divorcee reduced the chance of wedded bliss.
Nguyen Vi Cao, who led the research, promised: "If people follow these guidelines in choosing their partners they can increase their chances of a happy, long marriage by up to 20 per cent."
Relationship experts thought there might be something in the research.
Kate Figes, who interviewed 120 people for her recent book on understanding relationship, Couples, said: "Aren't most women the more intelligent in a relationship anyway? That's my first reaction.
"It's the only finding that rings true, from what I've found. Because it's women who tend to determine the emotional landscape of a relationship," she said.
"So I don't find it surprising that women should be more intelligent."
However, she warned that men should not resign themselves to stupefying passivity.
"Intelligent men understand that for a relationship to be happy, their partner has to be happy," she said.
Linda Blair, the clinical psychologist and author of Straight Talking, thought there could be an evolutionary reason for women to be the more intelligent partner in successful long-term relationships.
She said: "Going back to prehistory, women have needed to invest more in relationships than men, because men are more biologically adapted to spread their seed around."
They were therefore more likely to invest their intellectual abilities in maintaining that bond, she rationalised.
"But you can convince yourself of anything," she added.
However, Christine Northam, a marriage counsellor for Relate, said dismissively of the findings: "There are lies, lies and statistics."
She could not agree that wives should be more intelligent than their husbands.
"Modern marriage is about both of you having an input in the relationship," said Mrs Northam, who has been married for 41 years.
"It's about teamwork. It's not about one being dominant over the other."