▁high ; ▁new ▁tw in ▁data ▁and ▁models ▁with ▁struct ural ▁gen etic ▁variation ▁are ▁needed . ▁ ▁Gen etic ▁link age ▁analysis ▁has ▁been ▁incon clus ive ; ▁many ▁association ▁anal ys es ▁have ▁had ▁in ade qu ate ▁power . ▁Studies ▁have ▁exam ined ▁more ▁than ▁ 1 0 0 ▁candidate ▁gen es ; ▁many ▁gen es ▁must ▁be ▁exam ined ▁because ▁more ▁than ▁a ▁third ▁of ▁gen es ▁are ▁expressed ▁in ▁the ▁brain ▁and ▁there ▁are ▁few ▁cl ues ▁on ▁which ▁are ▁relevant ▁to ▁aut ism . ▁ ▁R isk ▁factors ▁Several ▁studies ▁found ▁a ▁strong ▁association ▁between ▁the ▁use ▁of ▁ac et amin oph en ▁( e . g ., ▁Ty len ol , ▁Par ac et am ol ) ▁and ▁aut ism ▁ ▁Aut ism ▁is ▁also ▁associated ▁with ▁several ▁pr en atal ▁factors , ▁including ▁advanced ▁age ▁in ▁either ▁parent , ▁di ab etes , ▁ble eding ▁and ▁use ▁of ▁psych iat ric ▁dru gs ▁in ▁the ▁mother ▁during ▁pre gn ancy . ▁Aut ism ▁was ▁found ▁to ▁be ▁indirect ly ▁linked ▁to ▁pre pre gn ancy ▁ob es ity ▁and ▁low ▁weight ▁moth ers . ▁It ▁is ▁not ▁known ▁whether ▁mut ations ▁that ▁arise ▁sp ont ane ously ▁in ▁aut ism ▁and ▁other ▁ne uro ps ych iat ric ▁dis orders ▁come ▁mainly ▁from ▁the ▁mother ▁or ▁the ▁father , ▁or ▁whether ▁the ▁mut ations ▁are ▁associated ▁with ▁parent al ▁age . ▁However , ▁recent ▁studies ▁have ▁identified ▁adv ancing ▁pat ernal ▁age ▁as ▁a ▁significant