Dear Doctor,

I am looking for pediatric-related guidance. Basically I have a two-year old boy (2 years, 1 month) who has not yet developed speech. He can recognize pictures and tells the word like cat, dog, papa, ball, car, etc. He also understands commands like 'let's go out', 'throw away the nappy', 'give me a kiss', etc. 

Lately we started playing with flash cards and he learned (and repeats) basic ones such as sun, moon, etc. Often, when given two pictures and ask him to give you one of them specifically, he does. He also knows where his nose is, and is also able to pull you to take you near a play area (inside the house). He also plays with his sister (6 year old). Looks at us when we call him and has also started imitating us - his sister sneezed last day and he has started doing it since then. Today - and this is something that has not been done for months - he saw his sister's playing push chair, lifted it up and spinned one of the wheels. He done this for say a minute (while looking around him) and then he moved away. 

He does not do any tantrums. 
My wife is desperately worried that the wheel spinning (the minute I referred to above) is a sign of autism. Can you kindly express your opinion please?

I really appreciate. Thank you.