Gardner RM, et al. – In this study, researchers investigated the link between paternal intelligence and autism spectrum disorder (ASD), considering co-occurring intellectual disability (ID) and attention-deficit hyper-activity disorder (ADHD), via a register-based cohort study design that included over 360,000 individuals with fathers conscripted to the Swedish military, resident in Stockholm, Sweden, born 1984-2008, and followed until December 31, 2011 for diagnosis of ASD, ADHD, and/or ID. In models adjusted for individual and family characteristics, high paternal IQ was noted to be correlated with offspring risk of ASD without ID/ADHD—an association that appeared to be driven largely by the fathers’ scores on the technical comprehension portion of the test. Conversely, an association of low paternal IQ with ASD+ID and ASD+ADHD was noted; low paternal IQ was strongly associated with ID and present also for ADHD without co-occurring ASD or ID. Association of paternal IQ to offspring risk of ASD was non-monotonic. The presence of co-occurring disorders was found to influence this association. Overall, phenotypic diversity among affected individuals was suggested, according to findings.