If the results from these three studies are combined, the overall proportion of left-handers is 13.3 per cent for autistic children and 8.3 per cent for matched controls, not a significant difference. However, if left- and mixed-handers are summed, then the frequency of non-right-handedness among autistic children is considerably higher than that found in age-matched normally developing children, although it is similar to that found in other children of the same intellectual ability (Bishop, D. V. M. (1990). Handedness and developmental disorder. London: Mac Keith Press. p. 111)
There is a close associated between handedness and maturational delay. There is a close association between autism and handedness. There is a close association between maturational delay and autism. There is a close association between a mother’s testosteone levels and her children’s handedness and autism.
Seems pretty clear that a mother’s testosterone levels are closely associated with maturation rate. There is a whole science devoted to maturation rates as those rates relate to evolution. That science is called heterochrony. Consider that autism is an evolutionary condition.
