Many families first notice autism spectrum disorder in the toddler years when a child isn’t meeting social and communication milestones as expected, such as limited eye contact, not responding to their name, or delayed babbling and words. Other early first signs of autism spectrum disorder can include repetitive movements (like hand-flapping), intense interest in specific objects, strong reactions to sounds or textures, or a preference for playing alone rather than with others. Sometimes the first clue is how ASD is first noticed at routine check-ups, where a pediatrician uses developmental screening tools and may refer the family for a full evaluation if concerns persist.