Taekwondo is a martial art for self-cultivation, which enables one to exert techniques in the air, using bare hands and unmeasured speed and power, and to embody the spiritual integration by means of cultivating spirit and energy to concentrate it on one thing.
This raises the possibility that, as yet, unmeasured psychological factors need to be considered.
Another explanation could be that there may be unmeasured correlates of precipitation, which themselves differ across counties, that may influence the occurrence of autism.
