Researchers have discovered that the "liberal gene" opens you up to new ideas and alternative lifestyles – and could influence your belief in left wing politics.
The findings may mean that liberals are born not made – although it is exacerbated if you an individual is popular during his or her young formative years.
The Liberal Gene is a "transmitter" in the brain called DRD4 which is connected to a chemical called dopamine, known as the reward currency of the brain.
When those with the gene are socially outgoing they seek out and are "rewarded" by other people's points of view, far more than they might be without the gene.
This suggests they are more open minded and tend to form less conventional political viewpoints as adults – especially if they have a socially active adolescence, says the study.
The research by scientists from the University of California and Harvard looked at 2,000 Americans.
It is published in the Journal of Politics.
It found those with a strain of the DRD4 gene seek out "novelty" – such as people and lifestyles which are different to the ones they are used to.
This leads them to have more liberal opinions, politically, it found.
The person's age, ethnicity, gender or culture appeared to make no difference – it was the gene which counts.
DRD4 is controlled by dopamine which affects the way the brain deals with emotions, pleasure and pain and can therefore influence personality traits.