Is the changing role of women in our society behind the rise in autism in the past 30 years?

The autism epidemic seen in most Western countries in the past 30 years is one of the great medical mysteries of our time.

The cause cannot be some great genetic shift – there simply hasn’t been enough time for this to have happened.

Our diets are not hugely different and there is nothing to suggest any other aspect of our lifestyles might be to blame.

One rather bizarre hypothesis, that certain combinations of vaccines given to toddlers might be to blame, has now been thoroughly discredited.

One ‘explanation’ is certainly over diagnosis; fifty years ago ‘autism’ was quite narrowly defined, a serious mental impairment which normally prevented sufferers taking a place in mainstream society.

Now children who are simply a bit obsessive or who show signs of social dysfunction are routinely labelled ‘autistic spectrum’ or ‘Asperger’s’.

But over diagnosis cannot explain all the rise – from one-in-2500 in the United States to around 1 per cent today (and similar rates in the UK).

For some years now Professor Simon Baron-Cohen (cousin of the comedian and actor Sacha), a psychologist at Cambridge University, has been developing his theory that something called ‘assortative mating’ may be at least partly to blame for the spectacular rise in autism diagnoses.

Associative mating: Professor Simon Baron-Cohen has said when two people who aspire to be doctors, surgeons or engineers get married, they are magnifying the chance of their child being autistic (posed by models)

The theory states that when people with strongly ‘systemising’ personalities – the sort of people who become engineers, surgeons, computer experts and who shine in some aspects of business – marry each other and produce children, the effects of this kind of ‘male brain’ are genetically magnified, increasing the chances of producing an autistic child – a child with what Prof Baron-Cohen suspects is an ‘extreme male brain’.

Strong ‘systemisers’ are often slightly obsessive, perfectionist and make great scientists and are often extremely talented at music. But they sometimes have difficulties socially interacting with other people – a combination of traits that can blend into the milder end of the autism spectrum.

Cambridge University’s Autism Research Centre is now asking members of the public who are graduates and parents to take part in a survey which will investigate any links between educational achievement, what kind of job they have and how their children develop.

Specifically, the new study will attempt to find out whether two ‘strong systemisers’ do indeed have a higher chance of producing autistic children.

Prof Baron-Cohen’s theory is certainly plausible.

Some of the sharpest increases in autism diagnoses have been found in Silicon Valley, in California – home to perhaps the largest population of successful systemisers on Earth, the tens of thousands of technicians, engineers and programmers who work in the computer industry. Inevitably, many of these people marry each other (there are now plenty of women working in IT, not the case a generation ago) and this is good (although circumstantial) evidence of the systemising-autism link.

But what about other places? Why the rise in autism just about everywhere? One answer could be the changing role of women in general seen in the last 100 years.

Equal opportunities: Now it is commonplace for women to become doctors or surgeons and marry

Until relatively recently in our history, being exceptionally bright was not much use to you if you were female. In Victorian Britain, for example, the opportunities for a woman to earn her living through brainpower alone were extremely limited.

According to the 1901 Census, there were fewer than a hundred registered female doctors in the whole of the United Kingdom.

Going to university was difficult and expensive – most did not even allow girls to study. There were certainly few opportunities for careers in engineering or the sciences.

You could become a teacher or a governess, or maybe, of you were exceptionally talented, earn your living writing or in the arts. Most of the professions were closed, as was the world of business.

Brainy women were not even seen as particularly desirable partners. Clever or rich men chose brides on the grounds of looks, ‘breeding’ or both.

Having an IQ in the 140s probably counted against you if anything. The traditional image of a ‘dumb blonde’ hanging off the arm of the successful politician or businessman was a horrible cliché but it had an element of truth.

And in any case, very clever women would have often been mad to get married.

"Fifty years ago, male airline pilots typically married stewardesses; now they marry other pilots. Doctors used to marry nurses; now they marry other doctors."

Until the 1880s British women who wed could not even own their own property.

If they she did have a job, many employers would automatically sack a girl the moment she turned up with an engagement ring. So many clever, ‘systemising’ women simply did not marry, or married late – and probably had fewer children when they did.

Now everything has changed. Not only have the legal and social barriers to women entering the workplace as equals been largely dismantled, we also have the phenomenon of the desirable ‘alpha female’. Fifty years ago many men were scared of smart women. Now, increasingly, alpha males want someone their equal or eve superior.

Fifty years ago, male airline pilots typically married stewardesses; now they marry other pilots. Doctors used to marry nurses; now they marry other doctors.

The wives of successful politicians are, increasingly, successful in their own right – and of course many successful politicians are women.

Prof Baron-Cohen points out that ‘alpha females’ are not necessarily strong systemisers.

Being a brilliant politician or writer may not require the sort of geeky ‘male brain’ that may lie behind the autism rise.

But the phenomenon of like-marrying-like may be having completely unexpected consequences that go far beyond mere equal opportunities for women.

It is a fascinating theory and we await the results of the new study with interest.