Parental age seems to be a factor in autism. As it is a factor in many gene deficiencies; as we get older, the biology of sperm and eggs change and defects are bound to result.
It is difficult to believe because we see so many very young couples with children with autism, so we know that it is not the age of the parents that determines that a child with have autism, but when many children of older parents have autism, it is a proportion matter.
Esther Berko, an M.D./Ph.D. candidate at Albert Einstein College of Medicine, Autism Speaks Predoctoral Fellow:
Now here comes the potentially confusing part. Though the risk of having a child with autism increases with parental age, the majority of children with ASD are, indeed, born to relatively young parents in their 20s and early 30s. Because the vast majority of children, overall, are born to younger parents, older parents would still have far fewer children with autism even if their risk is twice as high.
This is well put and is a modern, so to speak, way to think about finding the causes, understanding intervention outcomes, and forgetting about the cure debate.
Always, the hope is that this knowledge will lead to improved diagnosis, more targeted intervention and treatment options, and even opportunities for prevention.
Regarding intervention outcomes, there are also many, many factors that need to be looked at and there are researchers "on it." IQ, age at start, early progress, type and intensity of intervention, and many others are being studied as we speak and we have not found one answer. Except for the overal supremacy of behavioral interventions, of course. Behavioral interventions have been the most studied and the only with exceptional evidence of effectiveness.