Extensive empirical evidence indicates that the lesser variant of Autism Spectrum Disorders (ASD) involves a communication impairment that is similar to, but milder than, the deficit in clinical ASD. This research explored the relationship between the broader autism phenotype (BAP) among parents, an index of genetic liability for ASD, and proband communication difficulties. ASD probands with at least one BAP parent (identified using the Autism Spectrum Quotient) had greater structural and pragmatic language difficulties (assessed using the Children's Communication Checklist-2) than ASD probands with no BAP parent. This finding provides support for the position that genetic liability for ASD is associated with increased communication difficulties across structural and pragmatic domains.