Autism cause still a mystery

http://www.newscientist.com/article.ns?id=dn7076

While reading this article I was suddenly reminded of a short story I'd once read. It was in a little anthology of sci fi tales all dealing with god and religion, (I'm afraid I don't remember the name of the anthology, the title of the story or this particular author's name). At any rate, the story dealt with over population and the fact that as the population increased there was also an increase of children born essentially brain dead. An Eastern mystic (Buddhist?), discovers/infers that there are a finite number of human souls to be reincarnated and when that number is reached anyone born afterward is "soulless". The solution the story offers is to cut back on births, allowing the death rate to catch up, thus increasing the pool of souls from which the newborn may draw. Now, it's just offered as a piece of fiction, and I certainly intend on treating it as such. But it is weird to be facing a similiar tragedy that admits to no easy explanations a decade or two after the story was written. Very sad and very odd.