Mothers' intentions for adolescent sons' human papillomavirus vaccination in Japan: Psychosocial factors and relative influences across intention groups.

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by differences in social cognition and interactions, repetitive body movements or behaviors, and atypical responses to sensory stimuli. The prevalence of ASD has increased over the last 30 years. In 2022, the estimated prevalence of ASD among children aged 8 years in the US was 3.2%, with 4.9% in boys and 1.4% in girls. The diagnosis of ASD is made via clinical assessment of phenotype and likely encompasses distinct processes of multiple etiologies. The heterogeneity of ASD contributes to the multiplicity of associated predisposing factors, including complex genetics, parental age, environmental factors, and their potential interplay. While a higher ASD prevalence in males may reflect sex-based differences in recognition and diagnosis, the consistent predominance has motivated investigation of early-life, male-specific exposures, such as neonatal male circumcision (NMC), as potential contributors to neurodevelopmental differences. Two prior observational studies reported an association between male circumcision and ASD. A multinational retrospective ecological analysis of data from 1984 to 2005 indicated a correlation between NMC and ASD prevalence but may have been confounded by country-level differences in ASD diagnosis and reporting. A retrospective cohort study in Denmark, where circumcision is relatively rare, found a 46% increased risk of ASD among circumcised boys. However, these findings may have been biased due to unmeasured or residual confounding and misclassification and may not generalize to countries with high rates of NMC. The lay press has implicated NMC in ASD, citing pain from the procedure and provision of acetaminophen for pain relief as potential contributors. Given that previous research addressing this concern has limited generalizability and possible confounding and did not assess the role of acetaminophen, the relationship between NMC and ASD warrants examination. This study evaluated the association between NMC and ASD in a large, diverse prospective cohort of children in the US, where NMC is common.