Aggressive 21-month-old boy

This is a difficult problem. First, I'm very happy that you see the ill effects of smacking your son. It will not help at all to tell a child not to hit when you are hitting him yourself. That just gives the message that it's OK to hit someone as long as you're bigger.

Really, we are dealing with the temperament of your child. He is obviously very intense, and naturally at his age he doesn't have much control over his impulses. This does not make him 'bad', it just makes him very difficult to deal with.

As your son grows up, he will learn to control his impulses, especially if you start teaching him now. I assume that he wants to play with other children, as you often put him in social situations. He needs to be removed from them as soon as he does anything aggressive. As you remove him, you should tell him why by saying. 'No - we have to go now - you can't stay in the playground when you hit. We do not hit.'

This is of course very hard on you. But it is really the best way of teaching your child that he has to control himself to get what he wants.

He will certainly get better over time, especially when he has language. Until then, although it is difficult and embarrassing, you have to keep showing him what is right, praising him when he plays well (even if it's just for a few minutes), and removing him when he's wrong while stating the 'no hitting' rule.

I would also suggest that you not put him in social situations with other children too often, so that there is not so much pressure on him to 'behave', until you see he is having some success with controlling himself.