Archive for February, 2010

Age and Autism

Saturday, February 20th, 2010

The paper, Independent and dependent contributions of advanced maternal and paternal ages to autism risk by Shelton, Tancredi and Hertz-Picciotto released two weeks ago. It describes how older mothers are far more likely to have an autistic child.

Based on the first examination of heterogeneity in parental age effects, it appears that women’s risk for delivering a child who develops autism increases throughout their reproductive years whereas father’s age confers increased risk for autism when mothers are <30, but has little effect when mothers are past age 30. We also calculated that the recent trend towards delayed childbearing contributed approximately a 4.6% increase in autism diagnoses in California over the decade.

In 1998 I posted at sexualselection.org the hypothesis that older mothers will be discovered to be more likely to have autistic children because their testosterone levels are significantly higher. Simon Baron-Cohen conducted a number of studies that concluded that testosterone level in the mothers are directly connected to autistic tendencies. This study by Shelton, Tancredi and Hertz-Picciotto makes perfect sense in the context of mother’s testosterone levels impacting maturation rates, causing autism.


Handedness and Autism

Monday, February 1st, 2010

OBJECTIVE: Autism is referred to as cerebral lateralization abnormality. In this study, the possible relationships among handedness, eyedness and nasal cycle in autism have been investigated. MATERIALS AND METHODS: Thirty-seven children with autism and 20 controls were included in the study. The patient group included 27 boys and 10 girls who ranged in age from 5 to 20 years. For hand preference, hand used to write and throw a ball was accepted as dominant hand. For eye preference or dominance, eye used to look through keyhole of a door was accepted as dominant eye. Nasal dominance was assessed by a method of measuring the nasal airflow. RESULTS: The rates of left-handedness and left-eyedness were higher in children with autism compared to normal populations. A majority of children with autism had left nasal dominance. CONCLUSION: Autism and early language impairment may be associated with left handedness, eyedness and nasal dominance. (Dane, S. & Balci, N.(2007). Handedness, eyedness and nasal cycle in children with autism. International Journal of Developmental Neuroscience, 25(4), 223-6.)

Central to my understanding of handedness is Marion Annett’s theory that the left handed are really random handed, along with almost 10% of the right handers in society. What keeps coming to my mind is, if autism is increasing, and those increases are accompanied by estimations that it is just diagnosis that is more universal, then tell me if there are increases in left handedness. If there are increases in the left handed in this society, that suggests that there are increases in random handedness with is very likely the same as saying there are increases in male maturational delay.

If there are increases in both left handedness and autism, perhaps theorists can start offering attention to theories of autism that have to do with our evolutionary origins.


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