Left‐handers have a lower prevalence of arthritis and ulcer | Semantic Scholar

The controversy of other results in up-to-now investigations of health aspects of left-handedness may partly be explained by a scientific disagreement whether writing with the left hand is a sufficient criterium for left- handedness, or is it necessary to investigate other parameters for laterality assessment.

The maternal immune hypothesis might be extended or modified to account for the apparent interaction of older brothers and handedness, and two possibilities are considered: non- right-handed foetuses are insensitive to the presence of maternal anti-male antibodies, and mothers of non-right-handedfoetuses do not produce anti- male antibodies.