I am not sure if this is a silly question or not.
My son is 18 weeks old and I would say a clever little baby. He can sit on his own between 10-20 seconds. Look into mine and other peoples eyes, smiles back at me or laughs if I smile or laugh, currently learning his name and answers 70% of the time. He's very well behaved hardly cries, not irritated by things and sleeps very well.
But lately he has started flapping his arms a lot more his right one? I wasn't worried at all until I read it's a sign of autism.
Is this true or is this completely normal for a 4 month old baby