According to an expert in the UK, highly analytical couples such as scientists, engineers, physicists and mathematicians, are more likely to produce children with autism.

Professor Simon Baron-Cohen, of the University of Cambridge, says the impaired ability of people with autism to communicate, recognize emotions and socialize is linked with the same genes that enable a person to systemize, that is to find the laws that determines how a system works.

A weakness in these areas is the key characteristic of autism; it is estimated that around one child in every 100 has a form of autism and the vast majority of those are boys.

He says this may help explain the recent rise in diagnoses, while other argue that it is due to greater awareness and better diagnostic skills.

Professor Baron-Cohen terms people such as scientists, mathematicians and engineers as ‘systemizers’, and links the often diminished interest in the social side of life, and the obsession with detail, which makes them good at what they do, with the symptoms which characterize autism.

Such types, says Professor Baron-Cohen are often attracted to each other and are more likely to pass ‘autism’ genes on to their offspring.

A survey by the National Autistic Society which found fathers and grandfathers of children with autistic spectrum conditions are twice as likely to work in a systemizing profession, supports his theory.

It has also been found that students in the natural sciences have a higher number of relatives with autism than do students in the humanities, and mathematicians have a higher rate of autistic spectrum conditions compared with the general population.

Other research has also indicated that the parents of children with autism score highly on a questionnaire measuring autistic traits.

Brain scan studies of mothers and fathers of children with autism have revealed that the mothers have a masculinized pattern of brain activity, again suggesting they are strong systemizers.

Given the evidence from a number of sources a genetic cause of autism is not unlikely, with both parents contributing genes that ultimately relate to a similar kind of mind: one with an affinity for thinking systematically.

In the autistic spectrum of disorders the largest groups are classic autism and Asperger syndrome.

Both groups have difficulty developing social relationships, and find communicating with peers and others difficult.

Both also display unusually strong and often obsessive and narrow interests, and a strong adherence to routines.

In classic autism, the person might have an IQ at anywhere on the scale, sometimes in the learning disabled range, and the person invariably had a language delay as a toddler.

In Asperger syndrome however, the person is always at least average in IQ, and may be well above average, and talked on time as a toddler.

As a rule symptoms of the disorders do not manifest themselves clearly until around age two and even then can be difficult to diagnose.

The National Autistic Society, has welcomed the research, particularly any which fosters a better understanding of the nature and possible causes of autism.

The Society estimates that over half a million people in the UK have a form of autism, and say it is a lifelong developmental disorder which requires on-going specialist support.

The paper is published in the journal Archives of Disease of Childhood.