There is some data to suggest there may be a link.

However. The data is very limited. Mt sinai did a meta of 46 studies and found a link (not necessarily causal). A Swedish population study of like 2.5 million children found no link. Etc.

The modest increase that could exist is unclear and confounded. Is it Tylenol or is something that the Tylenol is being taken for? Eg if the mom is having frequent headaches or fevers is the underlying condition impacting development and making it look like Tylenol does?

But why?

Two big answers:

Kenvue (Tylenol manufacturer) is not exactly a “pharmaceutical giant”. They’re a much easier target for rfk to go after with much less in terms of resources. They absolutely will sue though and appear to be preparing to do so though. But going after vaccines (his big target), especially stuff like Covid vaccines, means going after real pharmaceutical giants. Moderna, Pfizer, Johnson and Johnson, etc. deeeeeep pockets and serious legal teams. This may be a fight he feels he can “win” to start gaining momentum and precedent.

IMO the bigger reason is political capital. He has a large following of desperate parents that want an answer for why their child has autism or intellectual disability. I know a lot of people on here are like “autism is a superpower” and that’s great but these people are stuck in the disability mindset. It’s also important to remember that autism is a broad spectrum. Some of these parents have children that are nonverbal, that can’t toilet or shower independently, that get extremely violent when frustrated, that need 24/7 assistance and will never live independently. Of course some of them are just frustrated that their otherwise fine kid isn’t “normal” enough but that’s a whole other frustrating thing.

They’re desperate for answers. The reality of the situation is that there isn’t a simple answer. The overwhelming evidence suggests a combination of factors: genetics, environmental, social and behavioral. But this is unsatisfying. I’ve worked with people on this for years and when you say “it’s probably a combination of factors” they are never happy with that. They want something to blame. This is the political capital. He is giving them that. Basically everyone has taken Tylenol within the past year. Most pregnant women will take Tylenol at some point for discomfort, pain, fever, etc.

Now they will not only have the answer to “what did this”, they will have him as a person to hold up as the savior who gave them the answer. I saw the same thing happen when I started around 2010. Even though it was years after it happened people still attached to Wakefield and were so grateful he gave them the explanation that it was the MMR vaccine. They’d “protect their other children” as a result by not vaccinating them. Didn’t matter if you pointed out Wakefields proven financial links to an alternative MMR vaccine, the retraction of the paper, him getting his medical license revoked, etc. That’s how desperate they are for answers. FWIW Wakefield is still super rich and got married to literal supermodels so that’s why he doubled down and probably a major factor in why rfk is doing the same