It is worth mentioning that one of the hypothesis that was studied by the researcher assistant teacher Hussien Ali Fakir, Department of physical Education and sports sciences at Bilad Alrafidain University college clarified newly in the research that puplished at Oxford university about the inheritance the left hand in human not physical;
Nature,
according to genetics field the left hand of human is not mendelian, but a kind of inheritance connected to the X chromosome, but appears physical There is not a relation to do with the hand, but the influence on the structure of the brain due to this trait  amazingly with 
Scholars previously by the instructions of the numbers with the sex , and this trait tends to the male more than female, also the result of the total percentage of those who uses the left about 11_12% of the global s population.