title: Seasonal variation in the birth of left-handed schoolgirls.
abstract: The birth of left-handed girls in a school population displayed a seasonal trend, with a peak in November. No seasonal trend was seen in the birth of left-handed boys. The seasonal pattern of birth of left-handed girls is compatible with the hypothesis that nongenetic factors contribute to the occurrence of left-handedness.
mesh_terms: D002648:Child; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006801:Humans; D008297:Male; D012621:Seasons; D012737:Sex Factors; D013696:Temperature