Does Circumcision Raise Autism Risk? Large New Study Says No

A fear has been circulating among some parents for years: could circumcising a newborn boy somehow raise his risk of developing autism? It’s a concern that has spread through online forums, parenting groups, and corners of the media. Now, one of the largest studies to examine the question has found no evidence to support it.

A study published in JAMA Pediatrics followed more than 2,700 male children across the United States and Puerto Rico and found no evidence that newborn medical circumcision was linked to autism spectrum disorder. After accounting for factors that could skew the results, the researchers found the procedure was not associated with an increased risk of autism, whether measured by an official diagnosis or by standardized behavioral screenings.

Autism spectrum disorder is a condition marked by differences in social interaction, repetitive behaviors, and unusual responses to sensory input. Its prevalence in the U.S. has grown over the past three decades. By 2022, an estimated 3.2% of 8-year-olds in the country had been diagnosed with it, and boys were affected at a much higher rate than girls. That gender gap has led some researchers and parents to wonder whether early, male-specific medical experiences like circumcision might play a role.

Where the Circumcision-Autism Concern Came From

Two earlier studies had raised the possibility of a connection. One used country-level data from 1984 to 2005 and found a statistical correlation between circumcision rates and autism diagnoses across nations, but that kind of broad comparison is widely considered vulnerable to misleading outside influences, including differences in how autism is diagnosed from country to country. A second study, drawing on records from Denmark, reported a 46% higher risk of autism among circumcised boys. Researchers behind the current study point out that circumcision is uncommon in Denmark and is performed mainly for religious or cultural reasons, meaning the results may have been skewed by factors the study could not fully account for, such as cultural background, family health-seeking behaviors, and how autism diagnoses were recorded.

Both earlier studies had limits that made it difficult to apply their findings to a country like the United States, where newborn circumcision is a routine hospital procedure across many different families and communities.

How Researchers Tested the Circumcision-Autism Question

Researchers drew on data from the Environmental Influences on Child Health Outcomes (ECHO) Cohort, a research program funded by the National Institutes of Health that pools data from pediatric research groups across the country. The analysis included boys from 14 sites across the U.S. and Puerto Rico, with data collected between February 2003 and September 2025.

Of the 2,771 boys in the study, 1,840 (66%) were circumcised before leaving the hospital and 931 were not. Overall, 192 boys (7%) had been diagnosed with autism. Among circumcised boys, 108 (6%) had an autism diagnosis, compared to 84 of the uncircumcised boys (9%). Before adjusting for other factors, the raw numbers actually showed a lower rate of autism in circumcised boys. Once the researchers accounted for variables like maternal education, family history of autism, parental age, and geographic region, the association disappeared entirely.

Beyond a formal diagnosis, the researchers also measured autism-related traits and behaviors using two standardized parent-report questionnaires designed to detect the presence and severity of autism-like characteristics. Neither measure showed a meaningful association with circumcision.

What About Acetaminophen and Autism?

One idea popular in some circles is that acetaminophen, the pain reliever commonly known by the brand name Tylenol, given after circumcision could somehow trigger or contribute to autism. Among circumcised boys in this study, about 4% received acetaminophen during the procedure, and roughly 7% were given it within 30 days of birth. Because use was so uncommon, the researchers reported it as a descriptive observation only, did not evaluate acetaminophen as a possible pathway between circumcision and autism, and drew no conclusions about an acetaminophen-autism link.

Researchers also broke down their findings by U.S. geographic region, whether a child was born prematurely, and whether a baby required a stay in a neonatal intensive care unit, a specialized ward for sick or early-born newborns. Across all of those subgroups, the pattern held: no increased risk of autism was linked to circumcision. One isolated finding in the Western region showed a statistically significant positive association, but the researchers noted it appeared in only one of many analyses, was driven by a single site, and may reflect a statistical artifact given the number of comparisons performed rather than a meaningful signal.

A key strength of this research is the breadth of children included. Participants came from 14 sites across the country and Puerto Rico, spanning the Northeast, Midwest, South, and West. About 26% of children were Hispanic, and the sample included families with a range of education and income backgrounds. Boys were born between 2003 and 2023, spanning two decades of data. Researchers ran the numbers again under slightly different conditions multiple times to make sure no single factor was distorting the overall picture. Results stayed consistent each time.

Prior research cited in the paper suggests that approximately one in two male newborns born in U.S. hospitals undergoes circumcision. For parents who have already had their sons circumcised and worried about that choice, or for those currently weighing it, this study draws on data from thousands of children tracked over years and finds that circumcision in the newborn period does not appear to be associated with an increased risk of autism.

Disclaimer: This article summarizes the findings of a single peer-reviewed study and is intended for general informational purposes only. It is not medical advice. An observational study of this kind can show whether two things are associated, but it cannot by itself prove that one causes or prevents the other. Parents with questions about circumcision, autism, or their child’s health should consult a qualified pediatrician or medical professional.

---