Fetal testosterone linked to autistic traits
Male hormone in the womb linked to kids with more autistic-like behaviours.
Researchers who having been tracking a group of children since birth have found that the level of testosterone they were exposed to in the womb is linked to whether they show autistic traits throughout childhood.
The children are now 8 years old. Questionnaires filled out by their parents show that those who had experienced higher levels of testosterone in the womb generally have better pattern recognition and numerical skills, such as remembering car number plates, but are less keen on socialising. None have been diagnosed with autism, but these are traits which, when taken to an extreme, are often present in autistic children.
The researchers at the University of Cambridge, UK, measured the level of testosterone in samples of amniotic fluid from 235 women who had tests for other clinical reasons, and have been following how some of the children develop ever since.
When 12 months old, babies who had experienced higher levels of testosterone in the womb tended to look at their mother less often, and at 18 months, they were more likely to have a smaller vocabulary than the others, the team has previously reported.
This latest update on their progress, presented by Simon Baron-Cohen and Bonnie Auyeung at the British Association's Festival of Science in York today, shows that the correlation between foetal hormone levels and autistic-trait behaviour continues as the children grow up.
Levels of foetal testosterone are thought to be mostly influenced by the baby itself rather than the mother. Baby boys produce more testosterone in the womb, which means they can also expose a non-identical female twin to higher levels of the hormone. But other genetic and environmental factors are thought to also play a role.
Links between testosterone and autistic traits have been suggested before, and found in animal studies. The Cambridge study is starting to show biological evidence to back up the theories, although they are still some way from showing whether testosterone levels actually cause autism.
Baron-Cohen's team is now embarking on the mammoth task of comparing data from 90,000 amniotic fluid samples from the National Danish Biobank with psychiatric records, to check for association between testosterone and diagnosis of autism.