The issue comes from the inability to establish a cause and effect relationship, John Hopkins states. Conflicting studies and recent rhetoric have sown confusion. Many studies are challenging to design and complete in an ethical manner. The issue is all of the other factors that come into play. The site mentions the ice cream analogy. There is a statistical association between eating ice cream and drowning, but the confounder is hot weather, which increase both ice cream consumption and the likelihood of swimming. It's suggested that a possible step forward is for an organization to bring together people with different types of expertise to assess and communicate where the evidence stands.
Margaret McCarthy was interviewed for Exploring the Evidence on Acetaminophen on Pregnancy with the National Academy of Medicine. She states that autism is on the rise because we are more aware of it and the signs; more people are seeking diagnosis. She mentions a meta-analysis that examined 46 studies, some of which found an association, but nothing was causal.
UC Davis MIND Institute shared these facts: autism has no single known cause, both genetics and environment play a role, the number of people taking Tylenol while pregnant have gone down while autism rates have gone up, more research is needed for this and for treatment/support for individuals with autism, and lastly, untreated fever in pregnancy can lead to serious issues while acetaminophen is one of the few safe options used to reduce it.
The FDA released a letter towards the end of 2025, important details are that the choice still lies with the parents. The Nurses Health Study and the Boston Birth Cohort study were used as evidence of association. It's also important to highlight the letter mentions even with these associations a causal relationship has not been established.