A deficiency in Vitamin D on the mother's side could explain why Autism Spectrum Disorder diagnoses are three times more common in boys, but don't start buying supplements. This was in rats and rats are not little people, there is a lot of ground to cover before this has human relevance. Low vitamin D in mothers is one of the many risk factors linked to Autism Spectrum Disorder, largely because it is a broad behavioral spectrum that has little scientific rigor in diagnoses, which means even less rigor in correlation. In the study, Professor Darryl Eyles and Dr. Asad Ali from University of Queensland found vitamin D deficiency during pregnancy caused an increase in testosterone in the developing brain of male rats. Vitamin D is important calcium absorption and most people get enough in their diets. In the United States, milk is fortified with it to offset declines that occur naturally during winter months.