[Hand-stretching reflex in children of different age and sex indicative for left- or right-handedness (author's transl)].

Young boys and girls when opening their mouth show an involuntary movement of one or both hands, i.e. slight flexion with maximal extension of fingers. The highest incidence of this "hand-stretching reflex" (HSR) is found in the age group of 4 to 5. Below this age more girls than boys are found with a positive HSR, whereas at the age of eleven girls are outnumbered by boys. Beyond this age the reflex disappears. Lefthandedness and leftsided reflex seem to correspond and vice versa. Lack of this reflex in the age group of 4 to 5 as well as persistence over the age of eleven seems to indicate retarded cerebral maturation.