Autism-like behaviour in children is linked to the amount of testosterone they receive whilst in their mother’s womb, according to a long-term study of behavioural changes in children carried out by Professor Simon Baron-Cohen at Cambridge University.
Whilst the report says that the study of 235 children shows a clear correlation between maternal levels of testosterone and the level of autistic traits shown by the children, it would be wrong to conclude that testosterone levels are a causative factor in the presence of autistic traits.
Professor Baron-Cohen’s earlier research has demonstrated a strong genetic link in autism and he has even identified the occupation that is most likely to be followed by those with autistic traits – engineering – a clue to the presence of autistic traits in deceased family members.
Baron-Cohen proposes a male-female continuum along which all our brains lie. At one end are extreme female brains which are highly empathetic. At the other extreme are very male brains, strong on systematising, but poor at empathising. Brains at the extreme male end of the spectrum demonstrate autistic traits. Male brains shade into female brains in the middle. Testosterone levels fall off towards the female end of the continuum, though not entirely.
My anecdotal observations are that men with extreme male brains are more likely to find a partner whose brain occupies the middle ground. The extreme female brain and the extreme male brain are likely to have little common ground. Extreme males find it difficult to socialise and are, I would suggest, more likely to meet their mate whilst studying or at work. Since they are more likely to be studying some subjects than others, and more likely to be working in some professions or occupations than others, and since those subjects or occupations are unlikely to attract many extreme female brains, it is more likely that the extreme male will meet either more extreme male brains or mid-range brains.
In other words, it is more likely that an extreme male will choose a mate with higher levels of testerone, since she is more likely to be able to systematise and they are thus more likely to share common interests and modes of thought. Were she to mate with a mid-range male, she would be unlikely to produce a child with autistic traits, but it is much more likely that the extreme male will carry the genetic code for autistic traits. In the event that the female has an extreme male brain herself, and mates with an extreme male, perhaps it is more likely that the child would be born with full-blown autism, rather than an asperger’s syndrome type pattern of traits.
Autism Research Centre, University of Cambridge, http://www.autismresearchcentre.com/arc/default.asp
‘Austistic Traits linked to testosterone in mother’s womb’, The Guardian, Wednesday, 12/9/2007, http://www.guardian.co.uk/science/2007/sep/12/autism
‘They just can’t help it: What kind of brain do you have?’, The Guardian, Thursday, 17/4/2007, http://www.guardian.co.uk/life/feature/story/0,13026,937913,00.html
Baron-Cohen, Simon, The Essential Difference: Men, Women, and the Extreme Male Brain, http://www.amazon.co.uk/Essential-Difference-Extreme-Penguin-Science/dp/0141011017/ref=pd_bbs_sr_1/203-7849429-8769522?ie=UTF8&s=books&qid=1189977085&sr=8-1