The development of societies as a whole has long been based on the characteristics and needs of right-handed individuals, forcing the less numerous left-handed individuals to adapt to this organization in order to better blend into the environment. In France, for example, left-handed people represent about 15% of the population.

It is at birth that one of the two hemispheres of the brain, the left or the right, will take the ascendancy over the other and will determine whether the person will be left or right-handed. Probably the most noticeable difference between a left-handed and a right-handed individual is in writing, as the direction in which text is written is from left to right, at least in Western culture.

Most right-handed people use the left hemisphere of their brain to process language, but that doesn't mean most left-handed people use their right hemisphere - that's a common myth, says Gina Grimshaw, PhD, director of the Cognitive and Affective Neuroscience Laboratory at Victoria University of Wellington in New Zealand.

About 98 percent of right-handers process language with the left hemisphere, she says, but so do about 70 percent of left-handers. Only about 30 percent use the right hemisphere or both hemispheres. "Most left-handed people seem to have similar language processing as right-handed people," Grimshaw says.

For other one-sided brain functions, such as attention, emotion, music and face perception, there is less data. "But for the most part, left-handed people are not obviously different from right-handed people. They certainly don't have an inverted brain."

A left-handed person will have more difficulty following this direction than a right-handed person, who can pull his or her pen from left to right while the left-handed person would have to push it to write. This difference often leads to more legible and uncluttered handwriting for right-handed people than for left-handed people.

This is one of the reasons why many left-handers have forced themselves to write with their right hand, thus becoming annoyed left-handers.

This adaptation, which was often imposed at an early age for some, allows left-handers to avoid having to contort their wrists to form letters inward by pushing the pen to the right and also allows them to be faster at writing. It is possible to identify a left-handed person at the very beginning of the writing cycle because the brain mechanics favors the natural direction of writing, which for the left-handed person is from the right to the left.

This natural tendency applied to the direction defined for Western writing, from left to right, would thus lead a left-handed person to write backwards, starting with the last letter of the word rather than the first.

In recent years, left-handedness has been studied more and more and feedback shows that this practice can have consequences on personal development and leave sequels such as strabismus and stuttering. Conversely, the qualities developed to adapt to a right-handed environment can forge a strong and determined character, useful in the choices and decisions that the left-handed person will have to make throughout his or her life.

https://www.neozone.org/societe/quelles-sequelles-et-consequences-pour-un-gaucher-contrarie/

Left-handedness appears to be associated with certain physical health problems. In a 2007 study published in the British Journal of Cancer, researchers found that left-handed people had a higher risk of breast cancer than right-handed people, especially for cancers that occurred after menopause. Although the two phenomena appear to be completely unrelated, Yeo believes they could both be the result of something affecting the fetus during early development. "We know that other physical vulnerabilities, such as low birth weight and prenatal head circumference, can predict later health problems," he explains. "How you develop in utero can set you on a trajectory for certain strengths and weaknesses for your entire life."
 Left-handed people are twice as likely as right-handed people to have Crohn's disease or ulcerative colitis, according to a British study.
The London researchers analyzed two national cohorts of people born in 1958 and 1970 who were given a questionnaire at the ages of 26 and 33. In total, the two studies involved 17,000 people.The authors found 71 cases of confirmed Crohn's disease or ulcerative colitis, with twice as many cases in left-handed people as in right-handed people.
The same risk was found when the two diseases were taken separately. Left-handedness has been associated with autoimmune diseases, asthma, migraine, autism and diabetes, but no one has yet been able to show why, the authors note.
The authors point to previous work showing seasonal variation in births of left-handed girls, which they say may involve environmental factors. Another somewhat controversial explanation is the level of testosterone to which a fetus is exposed in utero, which could affect brain and immune system development, they add.
In conclusion, there is some evidence that left-handed people are more receptive to covid 19 but there are no specific studies that prove this exactly.