Hi A.,
Yes I think it's too early for a 20mos old to start potty training. Is your son showing interest in his potty chair? If so, then may be get him to sit on it when you are using the restroom. My son is two and a half and I'm just now starting to potty train him, but doing it slowly because you can't force the issue. You have to gradually do it step by step. :-) If your son isn't showing much interest in his potty, then don't worry ok. He will in time. He'll start wanting to flush the toilet and come into the bathroom with you to see what you're doing. Go ahead and let him and that will help spike his interest. If you don't have a potty for him, get one to help encourage the interest and when the time comes, you'll know it's time to potty train. My son sits on his potty when I'm going, so when I can catch him on time, I can pull his diaper off and set him on his potty...usually he doesn't go in the potty, but in time he will. I hear from several people that boys usually take a bit longer than girls to potty train and it's not until they're well into their three's when they actually get the handle on using the potty. So you have time. :-) Best wishes, G.