A new clinical report from the American Academy of Pediatrics (AAP) makes recommendations regarding the clinical genetics diagnostic approach for children with intellectual disability (ID) or global developmental delays (GDDs). Chromosome microarray is designated as a first-line test, and consideration for inborn errors of metabolism is encouraged. The use of whole-genome sequencing is also discussed. http://pediatrics.aappublications.org/content/134/3/e903.full