6 Surprising Facts About Lefties

I dedicate this to my beautiful Mother who is left handed and awesome.

Southpaws. Lefties. Mollydookers. There’s no shortage of nicknames for the left-handed people of the world, even if much of everyday life seems to have been designed without them in mind.Hand preference remains an intriguing puzzle for scientists, with researchers still questioning why a small percentage of people favor their left hand over their right. This quirk has caused lefties to be saddled with historical baggage and ongoing inconveniences — unfortunately, The Simpsons’ Leftorium, where left-handed folks can find everything from can openers to cars suited to their needs, remains fictional.

We may still be working to uncover the origins of this unusual hand preference and to create a more lefty-friendly world,

but in the meantime, here are some curious facts about left-handed life.

Being Left-Handed Used To Be a Red Flag

For centuries, being left-handed in a primarily right-handed world wasn’t just inconvenient; it was also seen as suspicious or even dangerous. This bias goes way back: The word “sinister” comes from a Latin word of the same spelling meaning “on the left side.”

In medieval Europe, left-handedness was thought to have ties to witchcraft and, for some religious groups, demonic possession. These suspicions lingered for centuries — even into the early 1900s, left-handed schoolchildren in the U.S. and Europe were retrained to use their right hand instead.

These perceptions didn’t shift in any major way until the mid-20th century. Time magazine suggests one notable turning point came in 1968 with the opening of London’s  Anything Left Handed store, which celebrates southpaws rather than condemning them.

By the 1970s, more manufacturers were producing products specifically for lefties, and by the end of the decade, the number of people publicly embracing their preferred hand had risen from 2% in 1939 to approximately 12% in 1979.

Only 10% of the World’s Population Is Left-Handed

Only about one in 10 people worldwide are left-handed — or at least that’s the most accurate estimate the latest data can offer. As it turns out, pinning down an exact number is trickier than you might think. 

Some people write with their left hand but throw a ball with their right. Others, thanks to the aforementioned long-held misconceptions and stigmas, were flat-out forced into right-handedness as children, even if they innately favored their left hand.

Despite the margin of error, this 10% statistic has held up across time and cultures spanning more than 10,000 years. Modern tools, various teaching methods, and shifting social norms have all seemed to have negligible effects on this ratio, and that’s unlikely to change anytime soon. 

Genetics Are Partially Responsible

Left-handedness tends to run in families, but it’s not as straightforward as, say, eye color or blood type. Instead, it’s likely influenced by a combination of genetic, prenatal, and possibly even environmental factors. 

Research has identified rare genetic variants, particularly in a gene called TUBB4B, that appear 2.7 times more often in left-handed people than in right-handed people. Other studies suggest a left-handed preference may be detected in the womb as early as 10 weeks into pregnancy based on thumb-sucking activities. 

Handedness also appears to have an environmental component. In a 2019 U.K. study of more than 500,000 participants, the percentage of people identifying as left-handed increased steadily among those born each year starting from around 1920 until roughly 1970, when it leveled off. But this wasn’t simply because more left-handed people began to be born; instead, it was likely due to a decline in the social pressure to switch hands.

The study also suggested that low birth weight and being part of a multiple birth seems to increase the chance of left-handedness. Further research suggests seasonal hormone levels or exposure to infections may even make women born in the summer more likely to be lefties, but the exact reasons for these correlations remain murky and there are likely still other undiscovered factors as well.

Men Are More Likely To Be Southpaws

One pattern that consistently shows up in handedness studies is that men are more likely to be left-handed than women. The gap isn’t huge: about 12% of men versus roughly 10% of women prefer their left hand. Given the low number of lefties overall, though, it is statistically significant, and scientists still aren’t entirely sure why this is the case. One theory suggests hormones — specifically, higher levels of prenatal testosterone — may play a role. 

Even Animals Can Be “Left-Handed”

Favoring one’s left or right side isn’t solely relegated to humans; plenty of animals show their own versions of “handedness.” Kangaroos often prefer their left hand for grooming and feeding, and even tiny creatures such as bees can display side biases when navigating around objects. 

Dogs, too, will favor a paw, and there’s a way to test it beyond a paw shake: It’s called the Kong test. Give your dog a food-stuffed Kong or other treat-dispensing toy and watch which paw they use to hold it in place while eating. If they consistently favor one paw, that’s likely their dominant side. 

Some dogs may use both paws equally, but many demonstrate a clear preference. One study found that, among dogs that showed a clear paw preference, about 58% were right-pawed and 42% were left-pawed, making “left-handedness” much more common in dogs than in humans.