A study found that a pair of right-handed couples are only about 9.5% likely to have left-handed children. If one of the parents is left-handed, the probability of the child being left-handed rises to 19.5%. If both parents are left-handed, the probability of the child being left-handed is 26%. Therefore, the researchers believe that the habit of using left and right hands is genetically affected.
If true, the statement that a study of twins found that 50% of twins are left-handed and one is right-handed can weaken the above view.