I seem to often come across references to studies that observe that there is an increase in autism in children that are first born and children born of older mothers.
This leaves me with several questions.
Is there a clear exponential increase in the likelihood of autism in only children born later and later? Many parents would have an autistic child and then hesitate to have another child influencing the numbers.
As far fetched as this sounds, when children are adopted, does this same pattern apply of first born and older mother’s having autistic children? I can’t imagine this to be the case, but an answer might be interesting.
It is possible that there is a different etiology for younger mother’s with first born children having autism and older mothers having autistic children. I would guess that younger mothers might reveal causes related to stress factors or maybe lifestyle impacts that would influence testosterone levels. Do the specific features of an autistic child of a younger mother differ from the specific features of an autistic child born of an older mother? What of a mother who has her first child when she is older?
Opportunities to break out variations in autistic features in association with particular conditions would be useful in hypothesizing autism’s causes.
