What determines if a person is born left or right handed?

Answer 1

There is a lot of debate about what determines one's "handedness." From what I've read, it's not determined by any one factor. Handedness can be genetic, it can be learned, it can be pathological, or a combination of any of these.

Most people think handedness is strictly genetic (as did I), but many studies show that this is only a partial explanation for most people and unexplained in others. Right-handed parents will have right-handed children 92-96% of the time. Left-handed parents will have left-handed children 45-50% of the time. Also, twins (whether identical or fraternal), have a 20-30% chance of having opposite handedness, which means that genetics is not the only factor in handedness.

There are also theories that handedness is sometimes learned, based on what their parent's handedness is, but this probably only accounts for a very small percentage of people. The pathological theory has to do with trauma to a part of the brain before or during birth. This explains a larger percentage of left-handed mentally retarded people compared to the normal population (20-28% vs. 10%).

So to sum up, there are a number of reasons someone could be left-handed or right-handed, but none explain the phenomenon completely.

Answer 2

I have no clue, I think it just something that you are born with. My husband and I are both right handed and BOTH of our children are left handed, the only ones in the entire family, both sides.

Answer 3

Genetics

Answer 4

there isn't you teach that child to wright either right handed or left handed. or both