Season of birth and handedness in Serbian high school students.
BACKGROUND
Although behavioural dominance of the right hand in humans is likely to be under genetic control, departures from this population norm, i.e. left- or non-right-handedness, are believed to be influenced by environmental factors. Among many such environmental factors including, for example, low birth weight, testosterone level, and maternal age at birth, season of birth has occasionally been investigated. The overall empirical evidence for the season of birth effect is mixed.


METHODS
We have investigated the effect of season of birth in an epidemiologically robust sample of randomly selected young people (n = 977), all born in the same year. A Kolmogorov-Smirnov type statistical test was used to determine season of birth.


RESULTS
Neither the right-handed nor the non-right-handed groups demonstrated birth asymmetry relative to the normal population birth distribution. There was no between-group difference in the seasonal distribution of birth when comparing the right-handed to the non-right-handed groups.


CONCLUSIONS
The present study failed to provide support for a season of birth effect on atypical lateralisation of handedness in humans.
Milenković
Sanja
S
Institute for Hygiene and Medical Ecology, School of Medicine, University of Belgrade, Serbia.
Rock
Daniel
D
School of Psychiatry and Clinical Neurosciences, University of Western Australia, Australia.|Centre for Clinical Research in Neuropsychiatry, Graylands Hospital, Western Australia, Australia.
Dragović
Milan
M
School of Psychiatry and Clinical Neurosciences, University of Western Australia, Australia.|Centre for Clinical Research in Neuropsychiatry, Graylands Hospital, Western Australia, Australia.
Janca
Aleksandar
A
School of Psychiatry and Clinical Neurosciences, University of Western Australia, Australia.