Although no one knows how autism develops, experts have focused on physical causes such as environmental toxins, the vaccine preservative [[thimerosal]], and the diet of both the mother (pre-birth and during breastfeeding) and child. | Although no one knows how autism develops, experts have focused on physical causes such as environmental toxins, the vaccine preservative [[thimerosal]], and the diet of both the mother (pre-birth and during breastfeeding) and child. |