为什么有人是左撇子？ Why are some people left-handed?

If you know an older left-handed person, chances are they had to learn to write or eat with their right hand.

And in many parts of the world, it's still common practice to force children to use their "proper" hand.

Even the word for right also means correct or good, not just in English, but many other languages, too.

But if being left-handed is so wrong, then why does it happen in the first place?

Today, about 1/10 of the world's population are left-handed.

Archeological evidence shows that it's been that way for as long as 500,000 years, with about 10% of human remains showing the associated differences in arm length and bone density, and some ancient tools and artifacts showing evidence of left-hand use.

And despite what many may think, handedness is not a choice.

It can be predicted even before birth based on the fetus' position in the womb.

So, if handedness is inborn, does that mean it's genetic?

Well, yes and no.