A nurse is conducting a screening program for autism in infants and children. What would the nurse identify as a warning sign?

Choice A rationale Lack of babbling, which typically begins around 4 to 6 months of age and involves repeated consonant-vowel sounds, is a red flag for language and auditory processing difficulties, but a deficit by only 6 months may be early for a definitive autism warning sign. More characteristic early indicators are often related to a lack of social interaction and non-verbal communication. Choice B rationale Inability to say a single word (meaningful, not just sound) by 16 months is a key developmental red flag and strongly suggests a significant delay in expressive language, a core area often affected in autism spectrum disorder (ASD). This milestone should typically be achieved between 12 and 15 months; the absence at 16 months warrants further evaluation. Choice C rationale Lack of gestures, such as pointing, waving, or showing objects, by 8 to 12 months is a very significant early warning sign for ASD. Non-verbal communication, including gestures, is crucial for social interaction and joint attention; the absence of these spontaneous actions by 8 months indicates a potential delay in critical social skills. Choice D rationale Inability to use two words together meaningfully (two-word phrases) by 18 months is a recognized language delay indicator. While this is a general developmental red flag, the more typical warning sign for ASD specifically focuses on the lack of single words by 16 months or the absence of symbolic play and joint attention earlier on.