Can stress during pregnancy cause autism? what causes autism in babies

Doubt it/not clear: Advances in computer tech has led to an improved ability to study the human gene sequence. As they study autistic kids, they find many have mistakes in the gene code, like misprinted words on a page. The gene code, contained in the chromosomes at conception, tells the fetus how to form everything, include brain pathways affected by autism. It happens before conception. How is not clear.