In a sample of 1600 Dutch adolescent twin pairs I have found a very significant
difference in prevalence of lefthandedness (LH) among the oldest (=first born)
of all pairs: 16% among the oldest and 12.8% among the youngest. This holds for
all different zygosity catagories. This observation could be confirmed by
colleagues from the Univ. of Leuven in Belgium.
LH in parents of twins does not deviate from population values in the
Netherlands: about 10%.
Who has an explanation?
Free Univ. Amsterdam
e-mail: ko at psy.vu.nl