Autism - the new ADD.
Since both have quite easily demonstrable physiologic identification, we know how real they are. So yes, it really does make us wonder what is happening to make these conditions so much more prevalent in our population now. It's definitely not just that we're diagnosing these conditions more now--there's something very real, as anyone who works in the field can tell you.
Is it that improved heath care allows children to survive who would have perished in previous generations? I don't think that's supportable. I believe that we should start looking at the concerns of human health risk assessors, who are pointing out that considering the risks from individual environmental factors (e.g., chemical exposures) might underestimate the composite risk.
I do hope we discover the problem soon. Living with ADD or autism can be living hell.