The article published in the Archives by Stone et al1 on the early development of younger siblings of children with autistic spectrum disorders (ASDs) was certainly interesting and will hopefully pave the way for further research. The authors concluded that the weaker performance of siblings of children with ASDs may represent early-emerging features of a broader autistic phenotype. I was surprised that the authors did not include an alternative explanation in their discussions, that of parental availability for the younger unaffected sibling. The needs of the younger sibling for stimulation and comfort may be met with great difficulty by a parent struggling to balance the increased needs of the affected child with those of a new arrival. The child with ASD tends to require much closer parental supervision within and outside of the home, and the spectrum of family activities may be greatly narrowed by the vulnerability of the child with ASD to distress if exposed to novel stimuli. By contrast, novel stimuli are exactly what the younger sibling requires to maximize his or her developmental attainment. As Smith2 so eloquently describes in her article “Autism Through My Eyes,” social interactions outside of the immediate family, such as parties, may be very restricted by the needs of the child with ASD, the youngest child's opportunity to gain from wider social experience thus being reduced.
Reed RV. Parental Availability in Families Affected by Autism. Arch Pediatr Adolesc Med. 2007;161(11):1107-1108. doi:10.1001/archpedi.161.11.1107-a