On last Friday’s blog, I mentioned that around 10%-12% of the population is left handed. But what exactly determines which is our dominant hand? It’s not exactly known, but here are a few theories:
- A number of studies have shown that left handedness is genetic. So, if both your parents are left handed, there’s about a 50:50 chance that you will be as well. If one of your parents is left handed there’s a 20% chance you will be and if both your parents are right handed, there’s only a 2% chance that you’ll be a lefty.
- Prematurely-born babies and those with a low birth weight have a greater propensity to being left handed. This could be due to brain damage to the left hemisphere of the brain which means the right hemisphere becomes the dominant side.
- Another reason is when the mother produces high levels of the male hormone, testosterone, and passes this to her unborn child. This could be why there are more left-handed males than females.
- Left handedness occurs more frequently in identical twins. However, they aren’t usually both left handed. You’ll tend to find that, where one is left handed, the other will be right handed.
- There was a study done in Canada which showed that women aged 40+ are more than twice as likely to give birth to left-handed babies as younger mothers. This could be because older mothers are more likely to have birth complications.
3 comments:
Hello Carole, being a fellow southpaw I got the french connection immediately ;) When I was growing up I remember there was a general stigma attached to being a lefty but as time has moved on it only tends to crop up as a side comment e.g. "oh, you're left handed - that's strange!"
A major factor I think is that we have naturally adapted to a right handed world so scissors for example are typically designed for righties and I remember struggling with them when I was very young but now I couldn't imagine using a pair designed for lefties. I also use a mouse with my right hand.
It is interesting though as you, like me, have your widget panel on the right hand side - I wonder if there is something in that?
Jas
http://www.jasonslater.co.uk
I'm definitely a left handed mouse user. I switch the buttons over so I still click with my index finger.
About the widget panel: I didn't know there was a choice about where this panel goes. (I'm new to blogging, as you can probably tell...)
Carole
im a lefty, i have 2 brothers and one of them is left handed both my mother and father are right handed
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