C.T.
Just teach him to sit for now. He will want to be like a big kid later and will start standing up. And this is for the best because when he is a bit older he will have better aim. Believe me...it's MUCH less messy. You don't have to worry about re-training him. I have not known anyone who found it additional work later. He will be older and will just start doing it on his own to be like his Dad. Personally, I wish all men and boys would just sit to pee. I hate how so many men/boys splatter.