Why some percentage of people become Left Handers ?

Question

while majority of the pople are right handers some are born left handers ?

Answer 1

In my knowledge there is no such thing as a born left handers. A child is capable of using both hands with equal abilities, an alert guardian teaches the baby to use the right hand while eating, holding a pencil etc. otherwise a child tends to use both his hands. Those who were not taught to use their right hand as a kid becom lefties.

Answer 2

Because Right Handers Dont leave much percentage for them.

Answer 3

It is because right side of the brain,getting active.However in the right handers left side of brain which controls the movement of hand is active.This is the only mystery

Answer 4

Testosterone: According to one theory, exposure to higher rates of testosterone before birth can lead to a left-handed child.
Birth stress theory: Left-handedness may be due to stress at birth.
Ultrasound theory: A popular theory is that ultrasound scans may affect the brain of unborn children, causing higher rates of left-handedness in mothers who have ultrasound scans compared to those who do not. This is probably based on a few studies [9] [10]where this relation is studied. In one of these the authors claim that "...we found a possible association between routine ultrasonography in utero and subsequent non-right handedness among children in primary school." However later in the same article the authors state that "Thus the association ... may be due to chance" and "The result was not significant, suggesting that the study had insufficient statistical power to resolve the relationship between ultrasonography and subsequent left handedness in the child"

Answer 5

Scientists have found that the brains of left-handed people are shaped differently than those of right-handed people. Right-handers usually have asymmetric brains; their left cerebral hemispheres tend to be larger than their right hemispheres. In particular, Broca's and Wernicke's areas, two regions involved with language, are likely to be much larger in the left hemisphere than in the right. In contrast to right-handers, left-handers generally have more symmetrical brains, with similarly sized language centers in each hemisphere.
One possible explanation for this observation is that most right-handers have a "right-shift" set of genes. When these genes are active, the person will be right-handed and most likely will have a larger left cerebral hemisphere. If a person does not have active forms of these "right-shift" genes, there will be no genetic control over handedness or brain symmetry. These people can be either left- or right-handed, and their brains will be more symmetrical. A study by Daniel Geschwind and his colleagues at the University of California in Los Angeles adds support to the theory of genetic control over brain symmetry.

Geschwind and his team measured the volume of the left and right cerebral cortex in identical male twins and compared these volumes to handedness. Consistent with previous research, the left-handers had more symmetrical brains than the right-handers. Additionally, they compared the hemispheric volumes in each set of twins and found that right-handed twin sets were more likely to have similarly shaped brains than were twin sets in which at least one man was left-handed. These results support the "right-shift" genetic theory. It seems that there is genetic control over the asymmetry present in the brains of most right-handers. The loss of asymmetry in left-handed people may reflect a lack of this genetic control.

Other sites that may be of interest:
http://mo.essortment.com/whatdetermines_rbli.htm
http://www.nurseminerva.co.uk/handedne.htm

Answer 6

Some people have right side of their brain more active, they become left handers, commanly left side of a person's mind is more active so we are right handers.

Answer 7

via fact in seventeenth Century left handers have been burned, drowned and hung as witches or toddlers of the devil. Left handedness in French is gauche this ability clumsy, socially inept or incorrect. Even interior the early Seventies toddlers have been compelled to apply their appropriate palms to write if left exceeded or like me ambidextrous (use the two palms the two).

Answer 8

The human brain-cerebrum specifically, is divided into two parts called cerebral hemispheres. They are right and left cerebral hemispheres. Here is one magic! The left -side of our brain controls the right side i.e organs present in right side of our body. And the right of our brain controls left side of our body. If left part of our brain is dominating we tend to use right hand. Some people have their right part of brain dominating their body. So they become left handers.

Answer 9

I'm not sure, Myself and my brother are both lefties which is pretty unusual to have two siblings, but then quite afew of my cousins around my age group are too.

Answer 10

why do people become right handers, why are some people blind, why are some people tall/short.. please do ure study. research in the library