Be forewarned: the following is purely idle speculation on my part. Do not take this too seriously -- it's nothing but random thoughts on my part. I may be entirely wrong here.
When I think of the autistic community, certain "big names" come to mind. Most notably, I tend to think of Temple Grandin, Donna Williams, Jim Sinclair, Amanda Baggs, and Michelle Dawson (not in any particular order). Oddly enough, all but one of those names are female... and the sole exception is physically intersex and was raised as a girl.
At the same time, however, about 80% of diagnosed autistics are male.
In other words, we should expect that, all else equal, a list of notable autistics should have four men for every woman. The chance of this arising out of sheer coincidence is around .032% (0.2 to the fifth power), which, in my opinion, is fairly miniscule.
If it's not random chance, though, there has to be a reason. Unfortunately, there is an overabundance of potential causes for this, ranging from biological (e.g. hormonal) differences between the genders to differences in Western childrearing practices for boys and girls.
I suspect that the explanation involves the latter, in combination with differences in social expectations between the genders.