Leviton A, Kilty T
Arch Neurol. 1979 Feb;36(2):115-6. doi: 10.1001/archneur.1979.00500380085016.
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.
一所学校里出生的左撇子女孩呈现出季节性趋势,11月为高峰期。左撇子男孩的出生则未见季节性趋势。左撇子女孩出生的季节性模式与非遗传因素导致左撇子出现的假说相符。