Left-handed people are twice as likely to suffer from inflammatory bowel diseases as right-handers.

But scientists say they aren’t sure why and are calling for more research into the issue.

Previous studies suggest the amount of testosterone babies are exposed to in the womb might be to blame.

It may be that the male hormone affects not only the favoured hand but also the development of the immune system.

Other research has shown left-handers also have increased rates of asthma, autism, diabetes and migraines.

Now researchers from University College Hospital in London have found a link with bowel disorders such as Crohn’s disease and ulcerative colitis.

The researchers examined data from 17,000 people from two groups born in 1958 and 1970 in the UK.

Rates of both illnesses were twice as high among left-handers as right-handers, according to the research published in the medical journal Gut.