Fathers become more Left-wing if they have daughters because girls are more socially conscious, according to research.

Economists claim to have found a correlation between the number of daughters and sons in a household and their father's political views.

By analysing data in the British Household Panel Survey, they found that 67 per cent of parents with three sons and no daughters voted for Labour or the Liberal Democrats.

This rose to 77 per cent in households with three daughters and no sons. A similar pattern was found among families with two and four children.

Professor Andrew Oswald, from Warwick University, and Dr Nattavudh Powdthavee, of York University, wrote in an unpublished article that has been submitted to an economics journal: "This paper provides evidence that daughters make people more Left-wing, while having sons, by contrast, makes them more Right-wing."

Professor Oswald said that having daughters made men "gradually shift their political stance and become more sympathetic to the 'female' desire for a ... larger amount for the public good".

"They become more Left-wing. Similarly, a mother with sons becomes sympathetic to the 'male' case for lower taxes and a smaller supply of public goods," he said.

"Political feelings are much less independently chosen than people realise. Children mould their parents."

Researchers who looked at voting records of US congressmen before and after having children have found a similar pattern, with the arrival of daughters having a particularly strong effect on fathers.

However Arthur Mayne, a biologist with three sons, dismissed the approach as "simplistic" and said the idea that women were "more likely to be softer politically than men" could be seen as a stereotype.

"Recent studies seem to prove that women with higher levels of testosterone - who are more likely to display dominant, positive behaviours - seem to produce more sons than daughters," he said.

"Women with lower levels of testosterone, who are more likely to be empathetic and better listeners, tend to produce more daughters.

"It could be that the women who are most likely to produce daughters pick a partner who is closer to her more empathetic attitude to life.

"Hence people who are already more liberal may produce more daughters and those who are already conservative may produce more sons.
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