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How to Tell If Your Baby Will Be Right- or Left-Handed

You Can Tell If Your Child Will Be a Righty or Lefty Long Before They Pick Up a Pencil

As someone who writes and eats with her right hand but carries babies and bags and, weirdly, putts during a game of mini golf with her left hand, hand dominance has always intrigued me. Despite my varied preferences between my two hands, it turns out that my actual dominant hand, the right one, was likely predetermined long before I could ever hold a fork or pencil — it was apparent while I was still in the womb back in 1989.

A study recently published in Scientific Reports and led in Italy by Valentina Parma, researcher at the International School for Advanced Studies — SISSA of Trieste, and Professor Umberto Castiello of the University of Padua says that "hand preference is already well defined at the 18th week of gestation." Based on what most would consider to be involuntary movements in the womb at such an early stage, researchers were actually able to predict babies' motor preferences, which were then proven to be correct with 89 to 100 percent accuracy upon observing those same babies as 9-year-old kids.

For the study, the babies of 29 women with low-risk single pregnancies were observed via 4D ultrasound in 20-minute sessions from 14 weeks gestation. The number of movements with each hand was documented for each baby, and it was found that 25 out of 29 babies ended up being right-handed, while four became left-handed, which aligned closely with the researchers' predictions based on fetal movements from just 18 weeks gestation.

Although handedness sounds like a useless little tidbit you can discover about your unborn child, the study goes on to mention that being able to foresee a baby's hand dominance could help identify particular diseases and conditions "such as depression, schizophrenia, and autism spectrum disorders" that are often aligned with a certain handedness. "As an example . . . left-handed [individuals] are reported to more likely suffer from depressive symptoms and individuals diagnosed with autism spectrum disorder are significantly more left-handed than right-handed."

The study also states that a baby's movements and motions in the womb "could be used to identify new markers" that would aid in early interventions and "compensate for any development problems."

The jury's still out on whether or not handedness could be determined from your run-of-the-mill ultrasound sans close observations over time, but the study's researchers feel this information could be promising for future research surrounding the early diagnosis of some diseases and conditions and fetal developmental markers.

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