 It turns out that if you have a sibling who has autism, you do have a higher chance of developing autism. 20% of siblings of autistic children end up having autism, but 80% don't. So is there something environmental? Is it about the diet? Is it about antibiotic use? Is it about pesticides or herbicides that changes the microbiome, that pushes it into an imbalanced direction that may favor brain changes in kids?