We appreciate Dr Reed's thoughtful comments regarding the many everyday stressors experienced by families who have a child with autism. We agree that there are myriad family factors—including parenting stress, social support, and availability of emotional, financial, and other resources—that may affect the development of younger siblings of children with autism or other developmental disorders. Our intent was not to downplay the impact of family influences on the development of later-born siblings of children with autism—as it is clear that both genetic and environmental factors contribute to individual differences in children's learning and development—but rather to highlight the importance of monitoring the development of this group of children.
McMahon C, Stone WL, Yoder PJ. Parental Availability in Families Affected by Autism—Reply. Arch Pediatr Adolesc Med. 2007;161(11):1107-1108. doi:10.1001/archpedi.161.11.1107-b