What is the cause of birth defects that resulted in autism and attention deficit?

I know for a fact that birth defects like deafness, blindness, congenital heart and down syndrome are causes of german measles, chicken pox, high fever, asthma or mother conceiving babies in their old age and etc… but what causes autism and attention deficits? can they be acquired or really inborn?

StumbleUpon It!

Technorati Tags: , , , , , , , , , ,