Girls with Asperger syndrome may be better at masking their difficulties in order to fit in with their peers, and in general have a more even profile of social skills. But environmental and social factors may also play a part in sex differences in ability, which means that no direct analogy can be drawn between the poorer verbal skills of boys and the higher incidence of autism in males. In 1964 Bernard Rimland pointed out that, overall, males tend to be more susceptible to organic damage than girls, whether through hereditary disease, acquired infection or other conditions. Since it is now almost universally accepted that there is an organic cause for autism, it should not be surprising that boys are more vulnerable to it than girls. In recent years researchers have put forward a genetic explanation for the differences.
Girls inherit X chromosomes from both parents, but boys only inherit one, from their mothers.
Such behaviours can be extremely useful in areas of life such as engineering and science, where attention to detail and single-mindedness may be more valuable than social skills, for example. However, these are merely theoretical models and in fact researchers are still a long way from identifying a simple genetic cause for autism. It is likely that several genes on different chromosomes will be found to be associated with autism. This means that Skuse's theory, based on the X chromosome alone, may not represent the full picture. Various theories have been put forward for the excess of males with autism and Asperger syndrome, but the picture is far from complete and until we have a fuller understanding of the causes of autism, it is unlikely that a proper explanation can be reached.