People Born In Winter Are More Likely To Be Left-Handed, Thanks To The Seasonal Birth Effect

Whether or not you believe your fate is written in the stars, exactly when you were born may be able to predict a few key aspects of who you are. For example, did you know that people born in the winter are more likely to be left-handed? It's true — and science backs it up. A recent video from the Royal Institution of Great Britain gives us the lowdown on what's called the Seasonal Birth Effect and how it might link up to your dominant hand. Neat, right?

As we've been finding lately, your birthday really might have an effect on certain aspects of your health, personality, and more. It may not necessarily come down exactly to the month and day, and there's no astrology involved — but research has found some interesting correlations between the season in which you're born and… well, who you are.

The video is also careful to note that right now, all we can do is hypothesize — we haven't yet been able to determine whether there's actually a causal link. After all, tons of things can influence how babies develop, including the climate, diet, and exposure to sunlight the mothers experience while they're pregnant. All the same, though, the correlations are interesting; I don't know about you, but I'm looking forward to seeing additional research explore how your birthday might affect all these different traits.

Here's the general gist in five pictures; scroll down to see the full video — it's super cool, so I definitely recommend taking a few minutes of your day to watch it. Oh, and if you head on over to the video's YouTube page, you can check out links to all the studies mentioned in it. Three cheers for science!

1. What Is the Seasonal Birth Effect?

In short, it's when certain characteristics are linked to your date of birth. Apparently Hippocrates realized that what season babies are born in might be important way back in 460 BC, so it's not exactly a new idea; however, we're still working on teasing out all the details.

2. If You Were Born in the Summer…

You're more likely to be shortsighted or a smoker; however, you're less likely to suffer from schizophrenia or be left-handed.

3. If You Were Born in the Winter…

Remember how summer babies were less likely to suffer from schizophrenia or be left-handed? Well, if you were born in the winter, you're more likely to have those traits.

4. But Why the Heck Is That?

Research has shown that there's a pretty strong correlation between left-handedness and babies who were conceived in the summer and born in the winter. Why? Again, we don't totally know yet; however, scientists suspect it has something to do with the fact that pregnant women who conceive in the summer have more early exposure to sunlight than those who conceive in the colder months. That means that they're exposed to more solar radiation, which leads to something called oxidative stress.

The increase of oxidative stress is thought to affect the development of what's called brain naturalization — that is, when one side of the brain takes dominance over the other (you've heard of that whole “are you right brained or left brained?” thing, right?). Although the left hemisphere usually dominates, which results in right-handedness, an uptick in oxidative stress causes the right hemisphere to dominate — and voila: Left-handedness. I guess now we know when Westley and Inigo weren't born, right?

Left-handedness is also linked to schizophrenia, hence the higher chance that winter babies will develop the condition. So... yeah. Sorry, guys.

Watch the full video below:

The Royal Institution on YouTube

Imags: derekbruff/Flickr; The Royal Institution/YouTube (5); Panda Whale