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As a society we believe that our political allegiance depends on which party best marries up with our needs and values, and that these are shaped by our life experiences. 

But research with twins suggests picking who to vote for in an election might have more to do with your genes than the policies of the parties.

To put this to the test, the Department of Twin Research, which hosts the biggest adult twin registry in the UK, recently performed a poll of voting preferences.

Deciding who you will vote for may have more to do with your family than who won the leaders debate (above) finds study which looked at the voting habits of twins born in the UK. The aim was to explore how much nature and nurture influence our party political allegiances and potential voting preferences

The twins were all born in the UK and were broadly representative of the UK population. 

The aim was to explore how much nature and nurture influence our party political allegiances and potential voting preferences so we can draw broader conclusions about people's voting habits.

Twins provide a unique natural experiment for research. 

Identical twins share 100 per cent of their genes, while non-identical twins - like non-twin siblings - share about 50 per cent. 

Both identical and non-identical twins normally share the same environment while growing up. 

By comparing the differences and similarities between them we can identify how much of a quirk, disease, or trait is due to a genetic predisposition or environmental and cultural factors. 

Because twin studies adjust for culture and upbringing, they are an ideal way to study political allegiances.

The researchers analysed surveys completed by 2,355 twins (comprising responses from 612 full pairs) in March 2015 between the ages of 18 and 80 - most of whom were middle aged. 

They told the researchers whether they intended to vote, what their political party of choice was, and provided their personal rating of the main party leaders.

They found that voting Conservative, or not, is strongly influenced by genetics. 

When it came to voting Tory, they found that 57 per cent of the variability - differences or similarity - between people's voting preferences were due to genetic effects. This percentage is called heritability. 

That means the identical twins were more likely to vote the same way than the non-identical twins - suggesting an underlying genetic influence was stronger than environmental or random factors.

For UKIP voting preferences, there was also a moderately strong heritability of 51 per cent. This was closely followed by Labour and the Green Party both with 48 per cent.

The exception seemed to be voting for the Liberal Democrats, which was affected entirely by environment with no genetic influence. 

Identical twins showed exactly the same level of disparity in preference for the Lib Dems as non-identical twins. 

Geography also played a possible role - as voting for the SNP in Scotland was also completely environmental.

These latest results from UK data confirm the trends found in previous research carried out in the US.

The researchers analysed surveys completed by 2,355 twins in March 2015 between the ages of 18 and 80 - most of whom were middle aged. They told the researchers whether they intended to vote, what their political party of choice was, and provided their personal rating of the main party leaders

Voting for the Conservative Party, led by David Cameron, pictured above after voting at the last General Election with his wife Samantha, tended to have the strongest heritability according to a study of UK twins

A 2008 survey of 682 pairs of middle-aged twins from the Minnesota Twin Registry showed that self-reported political ideology and right-wing authoritarianism were consistently more similar in the identical twins than fraternal twins.

Previous studies have also shown strong genetic influences on right-wing views, be they for or against.

'We and others have demonstrated consistent genetic influences on all measurable aspects of our personalities,' said the researchers. 

'The consensus is that these political leanings are mainly due to the genetic makeup of our underlying personalities.'

'Despite this, our survey shows that whether we intend to vote or not does not seem to be influenced by genes and personality. That decision appears to be entirely shaped by environmental factors.'

The popularity of Nick Clegg (above), leader of the Liberal Democrats seemed to be heritable, although voting for this party was not heritability and appeared to be influenced by the environment alone, the study showed

The question of whether a leader would make a good prime minister produced mixed responses. 

David Cameron had the stronger genetic influence on opinions, with 50 per cent heritability, followed by Nick Clegg at 37 per cent. 

Views on all the other party leaders were purely environmental.

Psychology studies have shown our sub-conscious biases for leaders who are tall and with round symmetrical faces so maybe this also plays a role in our choices.

But even if we do see party leaders differently, the findings of this study suggest that our choices at the polling booth may not be as free or rational as we would like to believe. Something to think about when you approach the ballot box.

Professor Tim Spector is the Professor of Genetic Epidemiology at King's College London

Victoria Vazquez also contributed to this article.