Scientists have discovered why some people are left-handed
Are you a southpaw? Well, you might want to listen up, since scientists think they know why some people are left-handed. While it has to do with your body and your development, it seems as if your brain may not have any part of it. Shocker, right?
Our world today seems to favor righties — which is interesting, as a whopping 10% of us are left-handed. Back in the ’90s, studies revealed that older mothers — defined as women being pregnant in their 40s and beyond — were twice as likely to have a left-handed baby. Women who gave birth between the ages of 30 and 35 had a 25% greater chance of giving birth to a leftie. Psychologist Stanley Coren, who performed the study, said that older mothers had more reasons to be stressed, which could also play a role. This is a study we might want to pay attention to, especially since more and more of us are delaying motherhood. Perhaps if it pans out, lefties will rule the world someday.
But it turns out that there’s another key factor that contributes to whether someone will be left-handed.
Researchers are looking more at the spinal cord for clues as to what makes a person favor one hand over the other. Sebastian Ocklenburg, Onur Gunturkun, and Judith Schmitz did a study that was reported on by eLife. In it, they pinpointed the importance of gene expression within the spinal cord.
"In humans, asymmetric gene expression in the fetal cortex has been suggested as the molecular basis of handedness," their report reads. "However, human fetuses already show considerable asymmetries in arm movements before the motor cortex is functionally linked to the spinal cord, making it more likely that spinal gene expression asymmetries form the molecular basis of handedness."
The report states that even though the motor cortex isn’t yet connected to the spinal cord when a fetus is around 15 weeks old, the baby will already have his or her handiness sorted out — and that’s well before the brain becomes a big factor. Isn’t pregnancy baffling? The human body is an amazing thing.
We’re just happy that lefties are starting to gain a little more appreciation in the world. While they still need to buy some specialty products (like left-handed scissors) Business Insider notes that the Latin word “sinister” actually means “left hand,” which is a bit tough to grasp.
We’re sure that many more studies are going to be done to explain left-handedness in the future, and we can’t wait to learn even more. Maybe we will in time for International Lefthanders Day, which will take place on August 13th this year