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Old 03-13-2016, 06:44 AM
RivkahChaya RivkahChaya is offline
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Join Date: Feb 2012
Posts: 9,211
The reason that most people are right-handed, is that among those genes is a specific one that dictates that a person will be right-handed, absent something like being born without having a right hand, or having trauma to the left motor cortex, as happens in some birth accidents. 80% of the population has this gene. The 20% who do not, have even odds of being either right or left handed. This is seen in identical twins, 85% of whom are both right-handed, 10% of whom are right/left pairs, and only 5% of whom are left/left sets.

No one knows what causes right or left handedness in people without the gene, but people who have been looking at the phenomenon have noted that left-handers who write with a hook tend to have learning problems or motor skills problems, while people who write in a way the mirrors the way a right-handed person writes rarely have any problems, and the hook style is rarer. There is a theory that people who write with a hook may have the right-hand gene, but some problem that prevented them from being right-handed, and also contributed to their learning or motor skills problems.

My husband and son are lefties, and I have several cousins who are lefties. I write right-handed, but in the military, I fired my rifle left-handed, because my left eye was dominant. It wasn't uncommon. We had 60 women in my platoon, and 10 were lefties. Half the lefties fired right-handed, while 10 of the righties fired left-handed.