Does Newborn Circumcision Affect a Boy's Chance of Autism? A Large Study Offers Reassurance

What a 2026 study of 2,771 boys in a large US children's health research programme (McGrath et al., JAMA Pediatrics) found, and what it means for families

Some parents have worried that circumcising a baby boy might raise his chance of autism. A large US study of 2,771 boys has now looked carefully at this question and found no link: once family differences were taken into account, boys circumcised in hospital as newborns were no more likely to be diagnosed with autism than boys who were not circumcised.

Deciding whether to circumcise a newborn son is a personal choice, shaped by family values, faith, culture and medical advice. When worrying claims circulate about a common procedure, it is natural for parents to want clear, trustworthy answers. This article explains the new study, how it was done, what it found and what it cannot tell us [1].

Why anyone thought there might be a link

Autism, or autism spectrum disorder, is a lifelong difference in how a person communicates, relates to others and experiences the world, often including repeated behaviours or very focused interests that begin in early childhood [2]. It is common. In the United States in 2022, about 1 in 31 eight-year-olds had been identified as autistic, and boys were identified about 3.4 times as often as girls [3]. Around 70% of autistic people are male, and scientists think both genes and the environment play a part [4].

Because autism is so much more common in boys, some researchers wondered whether something only boys experience as babies could be involved, and circumcision was one idea [1]. In 2013 two researchers compared countries and found that those with more circumcision also tended to report more autism in boys. They suggested the real link might be paracetamol (called acetaminophen in the US), a pain medicine given around the time of circumcision, but they said themselves that this kind of country-by-country comparison cannot prove cause and effect [5]. That is because countries differ in many ways, including how often doctors look for and diagnose autism [1].

Then, in 2015, a study of 342,877 boys in Denmark reported that boys who had been circumcised were somewhat more likely to be diagnosed with autism before age 10 [6]. In Denmark circumcision is uncommon and mostly done for religious reasons, sometimes outside hospital, so the boys who were circumcised may have differed in other important ways from those who were not [1]. Other experts questioned the Danish results, pointing out that the finding depended on a very small number of boys [7].

The worry also drew on something true. Newborn babies do feel pain, and a study in Toronto found that baby boys circumcised without good pain relief reacted more strongly to their vaccinations months later [8]. That shows why pain relief matters, but it says nothing about autism. Meanwhile, ideas about paracetamol and autism have been studied in pregnancy too: a very large Swedish study found that when brothers and sisters were compared with each other, the apparent link disappeared, suggesting family factors rather than the medicine explained it [9]. Our article Familial Confounding and the Prenatal Paracetamol Question explores that story.

All of this mattered because circumcision is common in the United States. About half of baby boys born in US hospitals are circumcised, although the share fell from 54.1% in 2012 to 49.3% in 2022 [10]. In 2012 the American Academy of Pediatrics (AAP), the main US organisation of children's doctors, concluded that the health benefits outweigh the risks and that families who choose circumcision should be able to have it [11]; that statement formally expired in 2017 [10]. Until now, though, no large study from a country where hospital circumcision is routine had looked at autism directly [1].

How the new study was done

The study used information from the Environmental Influences on Child Health Outcomes (ECHO) Cohort, a large US research programme funded by the National Institutes of Health that follows children's health over many years [12][13]. The researchers drew on 14 ECHO study sites spread across the United States and Puerto Rico [1].

They included 2,771 boys, each born from a single pregnancy, whose medical records showed whether they had been circumcised in hospital as newborns and for whom information on any autism diagnosis was available. Of these boys, 1,840 had been circumcised and 931 had not [1]. The children were born between 2003 and 2023, and among the boys who were diagnosed with autism, the diagnosis came at an average age of just under 4 years [1]. This was an observational study, which means the researchers did not decide who was circumcised; they compared children whose parents had already made that choice.

They looked at three things: whether a doctor or specialist had diagnosed autism, and the boys' scores on two questionnaires that parents fill in about autism-like traits and behaviours. These questionnaires can flag children who might need a closer look, but they cannot diagnose autism on their own [1].

Crucially, the researchers took account of family differences that could affect both whether a boy is circumcised and whether he is diagnosed with autism: the mother's education, the parents' ages, whether autism ran in the family, and which part of the country the family lived in [1]. Imagine comparing ice-cream sales with sunburn: both rise in summer, but one does not cause the other. Adjusting for family factors is how researchers try to remove that kind of hidden "summer" effect.

What the researchers found

Before any adjustment, autism was actually diagnosed less often in circumcised boys: 108 of 1,840 (about 6 in every 100) compared with 84 of 931 uncircumcised boys (about 9 in every 100) [1]. This does not mean circumcision protects against autism. The uncircumcised boys were more likely to come from parts of the country where autism was diagnosed more often, and once the researchers allowed for these family and regional differences, the gap largely disappeared and was small enough to be explained by chance [1].

The questionnaire results agreed. Scores for autism-like traits and behaviours were essentially the same in circumcised and uncircumcised boys [1]. The researchers checked their findings in several other ways, for example by leaving out boys who had a family history of autism, or each study site in turn, and the answer did not change [1].

Paracetamol turned out to be rarely used. Among circumcised boys whose records described their pain relief, only 31 of 877 (4%) received paracetamol during the procedure; most had a numbing injection called a nerve block or a sugar solution by mouth [1]. In the first month of life, about 5 in every 100 boys in the study had a record of receiving paracetamol [1]. That means this study could not fully test the paracetamol idea, because too few babies received it to tell whether it made any difference, but it does show that most babies did not receive it. The records also revealed something useful for hospitals: pain relief was written down for only about half of the circumcised boys, a reminder that good record-keeping matters [1].

What the study cannot tell us

No single study answers everything, and the researchers were open about the limits [1]. Because it was observational, some hidden differences between families could remain. It looked only at circumcision done in hospital in the newborn period, so it does not tell us about circumcision done at home, for religious ceremonies or later in childhood. The 14 sites do not represent every family in the United States.

In one part of the country, the West, one questionnaire flagged more circumcised boys than uncircumcised boys as having many autism-like behaviours. This was not seen for actual autism diagnoses, nor in other regions, and the researchers think it may be a chance result of running many comparisons. They also note that it came mainly from one study site, where other differences between families may not have been fully accounted for [1].

What this means for your family

If you are deciding about circumcision for your son, this study offers reassurance that circumcision in hospital is not linked to autism. If your son has already been circumcised, the authors say their findings may offer reassurance [1]. The decision itself still depends on your family's values and on balanced information from your care team, which the AAP says parents are entitled to receive [14].

Pain relief remains important. The AAP advises that babies should always receive adequate pain relief for circumcision, and that a sugar solution alone is not enough [14]. A review of 35 studies found that a nerve block works best, although no method removes all discomfort [15]. It is reasonable to ask your team which pain relief your baby will have.

If you ever have concerns about how your child is developing, talk to your child's doctor whatever the circumcision decision was. Autism is often first identified at around age 4 [3].

What researchers are working on next

Scientists would like to repeat this kind of study in other places where circumcision is common, record pain and pain medicines more carefully, and study circumcision done outside hospital or later in childhood. The authors also stress that the safety of every medical procedure should continue to be watched over time [1].

The bottom line

This large US study found no link between hospital circumcision of newborn boys and autism, either in diagnoses or in questionnaire scores, once family differences were accounted for [1]. It does not show that circumcision prevents autism, and it cannot answer every question, but it offers families meaningful reassurance on a worry that has lingered for more than a decade.

References

  1. McGrath M, Li X, Jacobson LP, et al. Neonatal Medical Male Circumcision and Child Autism Diagnosis. JAMA Pediatr. 2026;180(10):1105-1115. doi:10.1001/jamapediatrics.2026.3239 ↩
  2. Lord C, Brugha TS, Charman T, et al. Autism spectrum disorder. Nat Rev Dis Primers. 2020;6(1):5. doi:10.1038/s41572-019-0138-4 ↩
  3. Shaw KA, Williams S, Patrick ME, et al. Prevalence and Early Identification of Autism Spectrum Disorder Among Children Aged 4 and 8 Years - Autism and Developmental Disabilities Monitoring Network, 16 Sites, United States, 2022. MMWR Surveill Summ. 2025;74(2):1-22. doi:10.15585/mmwr.ss7402a1 ↩
  4. Napolitano A, Schiavi S, La Rosa P, et al. Sex Differences in Autism Spectrum Disorder: Diagnostic, Neurobiological, and Behavioral Features. Front Psychiatry. 2022;13:889636. doi:10.3389/fpsyt.2022.889636 ↩
  5. Bauer AZ, Kriebel D. Prenatal and perinatal analgesic exposure and autism: an ecological link. Environ Health. 2013;12:41. doi:10.1186/1476-069X-12-41 ↩
  6. Frisch M, Simonsen J. Ritual circumcision and risk of autism spectrum disorder in 0- to 9-year-old boys: national cohort study in Denmark. J R Soc Med. 2015;108(7):266-279. doi:10.1177/0141076814565942 ↩
  7. Morris BJ, Wiswell TE. 'Circumcision pain' unlikely to cause autism. J R Soc Med. 2015;108(8):297. doi:10.1177/0141076815590404 ↩
  8. Taddio A, Katz J, Ilersich AL, Koren G. Effect of neonatal circumcision on pain response during subsequent routine vaccination. Lancet. 1997;349(9052):599-603. doi:10.1016/S0140-6736(96)10316-010316-0) ↩
  9. Ahlqvist VH, Sjöqvist H, Dalman C, et al. Acetaminophen Use During Pregnancy and Children's Risk of Autism, ADHD, and Intellectual Disability. JAMA. 2024;331(14):1205-1214. doi:10.1001/jama.2024.3172 ↩
  10. Yang P, Zhu X, Patel EU, Quinn TC, Grabowski MK, Tobian AAR. Trends in Circumcision Among Newborn Males in the US. JAMA Pediatr. 2025;179(11):1236-1238. doi:10.1001/jamapediatrics.2025.2464 ↩
  11. American Academy of Pediatrics Task Force on Circumcision. Circumcision policy statement. Pediatrics. 2012;130(3):585-586. doi:10.1542/peds.2012-1989 ↩
  12. Knapp EA, Kress AM, Parker CB, et al. The Environmental Influences on Child Health Outcomes (ECHO)-Wide Cohort. Am J Epidemiol. 2023;192(8):1249-1263. doi:10.1093/aje/kwad071 ↩
  13. Blackwell CK, Cella D, Adair L, et al. Extending the Environmental influences on Child Health Outcomes (ECHO) Cohort through 2030: Rationale and study protocol. PLoS One. 2024;19(12):e0312677. doi:10.1371/journal.pone.0312677 ↩
  14. American Academy of Pediatrics Task Force on Circumcision. Male circumcision. Pediatrics. 2012;130(3):e756-785. doi:10.1542/peds.2012-1990 ↩
  15. Brady-Fryer B, Wiebe N, Lander JA. Pain relief for neonatal circumcision. Cochrane Database Syst Rev. 2004;2004(4):CD004217. doi:10.1002/14651858.CD004217.pub2 ↩