The parent compounds of acetaminophen (US market in 1955 in the US as Tylenol and other products) were first discovered in 1886 (acetanilide) and 1887 (phenacetin). These were the earliest synthetic fever Tylenol (acetaminophen) does not cause autism. The FDA, in its statement that there may be an association, confirmed that "a causal relationship has not been established, and studies of millions of children Exploring the Evidence on Acetaminophen During Pregnancy Step Ahead ABA Acetaminophen and Autism: What You Need to Know Autism Research Institute