A few ASD cases have been linked to exposure to teratogens (agents that cause birth defects) during the first eight weeks from conception. Although this does not exclude the possibility that ASD can be initiated or affected later, it is strong evidence that ASD arises very early in development. Many environmental factors have been hypothesized to act after birth, but none has been confirmed by scientific investigation. These environmental elements can act as independent and significant risk factors, or they can potentially influence pre-existing genetic factors in people who have a genetic predisposition.
A few ASD cases have been linked to exposure to teratogens (ag.ents that cause birth defects) during the first eight weeks from conception. Although this does not exclude the possibility that ASD can be initiated or affected later, it is strong evidence that ASD arises very early in development. Many environmental factors have been hypothesized to act after birth, but none has been confirmed by scientific investigation. These environmental elements can act as independent and significant risk factors, or they can potentially influence pre-existing genetic factors in people who have a genetic predisposition