The Positive Predictive Value (PPV) of the Modified Checklist for Autism in Toddlers (M-CHAT), a parent report autism screening tool, is higher for males than for females (Ludwig et al., IMFAR 2011). Given the long waitlists and high costs for ASD evaluations, there is a need to reduce the number of false positive females on the M-CHAT. The current study examined the sex specific clinical profiles of toddlers who received an ASD evaluation based on M-CHAT screen positive status in order to explore potential differences that may contribute to the differential PPV of the M-CHAT in boys and girls. The sample included 250 males and 106 females (mean age=25.3 months, SD=4.6) who were evaluated based on screen positive status on the M-CHAT. Although children with ASD demonstrated greater ASD symptoms, lower IQ and weaker language and motor skills, minimal sex differences were discovered
