Scientists believe that babies that are exposed to high levels of testosterone while in the womb are more apt to develop autistic traits as children.
They are of the opinion that one of the generators of autism could be higher than usual quantities of the male hormone in fetal fluid.
The findings that are soon to be published support the hypothesis that looks upon autism as a genetic condition describing it as an "extreme version" of the male brain.
Earlier observations have indicated that high levels of testosterone in the womb affect do brain development and social development in childhood.
From Cambridge University, one of the world's foremost experts on autism, Prof Simon Baron-Cohen, explained the initial details of the study he led, yesterday, at the British Association Festival of Science in York.
Prof Baron-Cohen said: "The idea that fetal testosterone may play a causal role in autism is an existing hypothesis.
"There's no evidence that it's a causal factor, but this research is certainly consistent with that hypothesis."
As part of their study the scientists measured and recorded testosterone levels present in the amniotic fluid of 235 women who had undergone tests involving the extraction of fluid from the womb, known as amniocentesis.
Since then these women have given birth and their children have been accorded a series of tests. On reaching eight, the mothers of these children completed questionnaires specially engineered to look for indications of autism such as a child's preference for company or solitude and any exceptional skills at remembering numbers such as telephone numbers. The data, from these questionnaires were presented also at the British Association Festival of Science. The children have been scrutinized during this time, with regular testing for autistic-like behaviour during their development.
Baby boys generally produce double the amount of testosterone that baby girls do. On examination of the amniotic fluid it w as found that the levels differed by as much as 20-fold, from 0.1 nanomoles per litre to over two nanomoles per litre.
It was also observed that those exposed to higher concentrations of the male hormone scored higher points in the questionnaires.
Besides this they did better in a test in which those with autism typically excel at-finding hidden shapes.
"Children with autism seemed to have an exaggeration of the typical male profile because they have a very strong interest in systems, like numbers, but have difficulties with empathy," Professor Baron Cohen added.
However, the professor believes the condition should be recognized as an atypical form of development, like left handedness, but not cured.
It may be noted that hormones within the amniotic fluid are manufactured not by the mother but by the fetus itself. In spite of this the professor reiterated that his studies did not demonstrate that higher testosterone levels caused autism.
Remarking that as the evidence was only a correlation, all they could say was that fetal testosterones are correlated, but they could not infer that it caused the malady.
"We don't know if the fetal testosterone is causing the autistic traits or is a by-product of them."
Neither could they provide a definite reason as to why some unborn babies produced more testosterone than others.
Bonnie Auyeung, one of Cohen's graduate students who participated in the study remarked that the genetic factor also probably contributed to the development of the condition.
It is believed that the main reason for the increase in the number of cases with autism, is improved diagnoses and the extension of the definition which now also includes milder symptoms of the malady.
If testosterone levels are shown to be responsible for autism, even partly, it will raise the issues such as that of ethics. Lowering testosterone levels in the womb deliberately may lessen risks of autism, but it would definitely interfere with normal fetal development, which is why people are still of two minds as to whether autism should be 'healed' or not.
The team has been awarded an additional grant by the Medical Research Council in order to cross reference 90,000 amniotic fluid samples from Denmark with one of their psychiatry registers to study it and determine whether the children diagnosed with autism received higher levels of testosterone.
