Handedness of a child

Left-handedness does not have a simple inheritance model. According to studies of twins and their families, about 25% of left-handedness can be explained by the influence of genes, while the remaining 75% is determined by the influence of the environmental factors.


  • 10-09-2021
Handedness of a child

A left-handed person (“leftie”) is a person who prefers to use left hand instead of right. Approximately 10% of the population is left-handed.

Left-handedness, like many other human traits, is influenced by many factors, including genetics and the environment.

Scientists for many years have been trying to find the cause of left-handedness, conducting a lot of research. So far, scientists have come to the conclusion that genetics is responsible for about 25% of left-handedness, and the remaining 75% is the influence of the environment.

In addition, studies show that left-handed people have a slightly higher risk of developing schizophrenia, but a lower risk of Parkinson's disease. There is also speculation that lefties may have better verbal skills.

Most children have a preference for using the right or left hand by about 18 months of age, and by the age of three, you can almost certainly determine that a child is left-handed or right-handed.


It was believed that one gene is responsible for left-handedness. However, recent studies suggest that a person becomes left-handed under the influence of about 40 genes. Each of these genes is likely to have minimal influence on its own, but together they play a significant role in the preference of a particular hand.

Left-handedness does not have a simple inheritance model. Children of left-handed parents are more likely to be left-handed than children of right-handed parents. However, since the percentage of left-handed people is quite small compared to right-handed, left-handed parents in most cases will have right-handed children.

The handedness genetic calculator calculates the probability based on statistical data. Although according to some studies, it is possible to find out which hand the child prefers from the 13th week of pregnancy, the environment has a rather large impact, as a result of which, preferences can change.

In 18 percent of identical twins one twin is right-handed and the other left-handed.

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