Jessica Wynn

But that's the big question.

Nature and nurture are both going on in the womb, too.

So the brain starts picking sides before you even have thumbs, actually.

Scientists have been chasing the genetic side of this for decades.

I mean, genetics is definitely a part of it, but it's not the only thing pulling the strings.

It's many small genetic effects, plus the prenatal environment, and then some good old-fashioned randomness.

No, not at all.

Children of left handed parents are more likely to be left handed, but the probability is still pretty low.

And most children still turn out right handed.

So heredity has a genetic component.

So it does raise the odds, but it doesn't seal the deal.

Like, are your kids left handed?

Yeah, it's rare.

I mean, do they ever try to copy the way you do things, like a little left-handed mimic phase or anything?

Right.

Yeah, they probably don't have that concept yet because it is just a natural dominant thing we do.

And it would be a significant challenge to, as an adult, try and use a less dominant hand because handedness is decided long before anyone picks up an instrument.

And studies show that in the womb, fetuses start showing little quirks like a head-turning bias, meaning some turn to the right more often, which means they get more sensory feedback from that side.

That feedback reinforces right-hand use later on, and vice versa, left-turners end up left-handed.

Yeah, because there's balancing involved.