Prevalence of autism diagnosis has historically differed by demographic factors. Using data from 8224 participants drawn from the Environmental influences on Child Health Outcomes (ECHO) Program, we examined relationships between demographic factors and parent-reported autism-related traits as captured by the Social Responsiveness Scale (SRS; T score > 65) and compared these to relations with parent-reported clinician diagnosis of ASD, in generalized linear mixed effects regression analyses. Results suggested lower odds of autism diagnosis, but not of SRS T > 65, for non-Hispanic Black children (adjusted odds ratio [OR] = 0.76, 95% CI 0.55, 1.06) relative to non-Hispanic White children. Higher maternal education was associated with reduced odds of both outcomes (OR = 0.73, 95% CI 0.51, 1.05 for ASD autism diagnosis and 0.4, 95% CI 0.29, 0.55 for SRS score). In addition, results suggested a lower likelihood of autism diagnosis but a higher likelihood of an SRS score > 65 in Black girls. Findings suggest lower diagnostic recognition of autism in non-Hispanic Black children, despite a similar degree of SRS-assessed autism-related traits falling in the clinically elevated range. Further work is needed to address this disparity.