Can lead on a toy that my child has played with cause schizophrenia when he grows up?

No: To the best of my knowledge, no. Lead exposure causes decreased iq, can affect attention, vigilance, language development, and memory. It's also associated with increased aggression and antisocial behaviors. Even low levels can produce negative affects. The best lead exposure is none at all, which is why leaded gasoline and paint are no longer used in this country.

MAYBE: While there are not great studies clearly linking blood lead levels to higher incidence of schizophrenia, there is some date to suggest they are related. Studies (like one published in nature in 2004) have linked elevated lead exposure before birth. That study showed that moms with high lead levels in pregnancy were twice as likely to have schizophrenic children. But genetics play a clear part to.