"Robert F. Kennedy Jr. said that early infant circumcision doubles the rate of autism"

Question

One of the newer claims by Robert F. Kennedy Jr. suggested that infant circumcision doubled the incidence of autism and that it is "highly likely" caused by pain or medication with the circumcision. Fact-checkers like Al Jazeera went over the studies that he used to make his claim and found that those studies do not support his claim. The studies are small, observational, and reveal no causality between circumcision and autism. Also, there is no evidence that drugs like acetaminophen are to be blamed. Experts note that there is no scientific agreement between circumcision and autism, and the claim misleadingly suggests correlation as causation. In conclusion, the claim is false and baseless. Source

Answer 1

The claim that circumcision causes increased rates of autism, one originally made by Robert F. Kennedy Jr., is both inherently false and a classic confusion between correlation and causation. In an article written by Sara Moniuszko for CBS news, Moniuzsko states that "The authors admitted that national and state averages may show correlation, not causation, and said their study may have mistakes, bias and confounding". In his original statement, RFK Jr. mentioned two studies without actually citing them, so the actual origins of his claim are unknown, although it is speculated to be from a 2012 study and a 2015 study that show similar findings. In addition to this claim, Moniuzsko also shares that RFK claimed that it was a  2025 study that "directly validates my point that the observed autism correlation in circumcised boys is best explained by acetaminophen exposure, not circumcision itself."" In either case, the links are not solid. Just because someone is circumised at a young age and receives acetaminophen as pain management, there is no guarantee that there is an increased likelihood of autism.  

Despite this overwhelm of negating information, it is also important to look at the political bias and leaning of the sources involved. CBS news has a historically left leaning political affiliation (All Sides Rating). JFK Jr. is a republican and tends to have more conservative views closely aligned with those of current U.S. President, Donald Trump. 

A second source debunking this claim Allison Parshall of Scientific American. Parshall, in reference to the 2013 and 2015 studies, states that "neither study shows a causal link between circumcision—or the pain relief medications that are often prescribed along with the procedure—and higher rates of autism". RFK Jr.'s claim has no factual backing. Despite his insistence that Tylenol and circumcision cause autism, there is simply not a causational relationship present. 

Again, it is important to check the potential bias of the sites. Scientific American as a source has, like CBS News, a left leaning bias (All Sides). The same potential issues with the differences in political viewpoints between the source and RFK Jr. are present. 

In short, the claim made my RFK Jr. that circumcision causes increased rates of autism is decidedly false. 

Answer 2

This claim is false. Aljazeera notes that Robert F. Kennedy Jr. claimed on October 9, 2025, "There's two studies that show children who are circumcised early have double the rate of autism, and it's highly likely because they're given Tylenol." However, the studies RFK Jr. listed are linked to correlation, not causation. The 2013 study, authored by UMass-Lowell epidemiologists, was a "hypothesis generating" exercise, meaning there was no intent to correlate acetaminophen and developing autism. Circumcision was also not the focus of the study. The 2015 Denmark study focused on whether being circumcised meant a boy was more likely to be diagnosed with autism before the age of 10. Both the studies note their small sample sizes and limitations, as well as not including data on acetaminophen being given to the patients of the studies or circumcision being a cause of autism. 

Scientificamerican.com also speaks on the inaccuracy of RFK Jr.'s claim, referencing Helen Tager-Flusberg, an autism researcher and professor at Boston University who leads the Coalition of Autism Scientists, a group that advocates for high-quality autism research. Tager-Flusberg calls the methods used in the studies "appalling." More information about the 2015 Denmark study was provided. The study involved 3,347 predominantly Jewish and Muslim boys who had been circumcised due to religious reasons, and found that this group of boys showed a higher likelihood of being diagnosed with autism than those who haven't been circumcised. Psychologist David S. Mandell, a member of the Coalition of Autism Scientists, tells Scientific American, "that study is riddled with flaws, which others have written about." In the years since these studies were published, autism researchers have continued to criticize them. The researchers and Scientific American point out the constraints on observational studies like these, as these studies cannot explain what causes autism. 

Overall, correlation does not equal causation, and Robert F. Kennedy Jr's claim is false/incorrect.