I just stumbled upon this article from 6 months back on Ali G's brother's Empathizing-Systemizing theory of autism and his new book, The Essential Difference (about mindblindness in the context of male-female differences). But what caught my attention was a dissent from Baron-Cohen's thesis:

A British researcher, for example, has found that the sex ratio was equal in autistic blind children, and that there is a different sex ratio in high IQ versus low IQ people with autism. ``So it's not just a male thing; there's something else going on,'' she said.

After a little digging this is what I found:

...boy:girl ratios in the most severely retarded groups being in the range of 2:1 rather than the much cited ratio of 3-4:1 for the autism group as a whole (Rutter, 1985) and 9-10:1 for the Asperger group....

Whatever is going on, it's complex. Like schizophrenia, the genetically heritable component of autism/Asperger's Syndrome is polygenic (assuming you believe there is a unitary phenotype of Autism or Asperger's Syndrome). The point about blind children to me is more interesting than the IQ differences, could there be essential visually cued inputs that blind girls miss that results in their 'mindblindness'? (I am thinking along the lines of being able to read facial expressions and match them to emotional states) Or might it be that blind boys do not get the visual inputs that trigger their interest in mechanics and the movement of objects, allowing their social skills to develop to a greater extent?

Related: Another article on Baron-Cohen. Also, The Autism Research Centre.