I have a friend with an autistic kid. The kid is 3 can't talk and doesn't respond to facial expressions, along with a long list of specific easily recognizable common behaviours. The idea that these common traits would have not been diagnosed by previous generation of educators is wishful thinking at best.

Key signs of autism in children include:

1. Social communication difficulties: Lack of or limited eye contact Difficulty understanding and using nonverbal communication (e.g., gestures, facial expressions) Trouble with understanding and using gestures, body language, and facial expressions Difficulty developing and maintaining age-appropriate relationships with peers Challenges with sharing interests or enjoyment with others Repetitive behaviors and restricted interests:

2. Engaging in repetitive movements (e.g., hand-flapping, rocking, spinning objects) Insistence on sameness and routines; becoming distressed by changes in routines Intense focus on specific interests or topics, often to the exclusion of others Communication difficulties:

3. Delayed speech development or difficulty in acquiring language skills Unusual patterns of speech, such as echolalia (repeating words or phrases out of context) Difficulty initiating or sustaining conversations Challenges in understanding and using language pragmatically (e.g., taking turns, using appropriate tone of voice) Sensory sensitivities:

4. Heightened sensitivity to sensory stimuli, such as noise, lights, textures, or smells Seeking or avoiding certain sensory experiences (e.g., seeking deep pressure, avoiding crowded places)

5.Unusual play and behavior:

Engaging in repetitive and imaginative play that lacks social aspects Using toys in unusual ways or showing little interest in toys altogether Engaging in self-stimulatory behaviors (stimming) to self-regulate or express emotions"