Being born a lefty doesn't mean you've been dealt a bad hand

Around one in 10 people are born with a preference for using our left side. But while being left-handed has drawbacks in a world designed for right-handers, there are some surprising advantages too. Here Tanith Carey explores the pros and cons of left-handedness and what they can mean for your health

- Tanith Carey

Why are we left-handed?

Whether you are leftor right-handed is largely ruled by how your brain is wired before birth.

Each hemisphere of the brain controls the opposite side of the body. So if your left hemisphere is more dominant, you are most likely to use your right hand, and vice versa.

Having one dominant hand may seem like a quirk, but there is likely a good evolutionary reason. It would take longer and mental effort to constantly swap hands for the same tasks.

Preferring one hand saves time and energy, a tendency that can be spotted even before birth. A recent study from the International School for Advanced Studies in Trieste, Italy, found foetuses start preferring to use one hand more than the other as early as 18 weeks.

The scientists discovered this accurately predicts which hand the child will favour after birth in 100% of cases.

However, whether you are leftor right-handed usually only becomes clear when toddlers begin to develop fine motor skills and start to draw or use cutlery at mealtimes.

Evidence of human left-handedness can be seen through history, with archaeological finds of tools adapted for left-hand use dating back half-a-million years.

You are likely to be left-handed due to a combination of genetics and environment. So if you have a left-handed parent, you are up to 25% more likely to be left-handed too.

Gender also plays a role

Around 12% of men are left-handed, compared with 8% of women.

Researchers believe this is because the fluctuations of hormones like testosterone to help boys become more masculine can also affect the development of the brain's hemispheres in the womb.

IF YOU'RE LEFT-HANDED YOU'RE MORE LIKELY TO...

Be more accident prone