Petite, Small, Husky, Large

Twice a year I shop for my children. OK more than that but I actually devote time to their clothes twice a year for the season change. This year I noticed something that is a little disturbing. My son, who will be 8 this summer, is small. If he were a girl we would say petite but not the best word for a boy. Anyway, I have a difficult time finding shorts that fit his waist but don't make his legs look too skinny. Most of the clothing that I have bought for him this year is a size 6. On the other hand my daughter is big for her age. She will be 5 in a few weeks and I bought size 5 clothing only to return it because it did not fit. The point is that I am now buying size 6 for both my 8 year old son and my 5 year old daughter. I want this to be switched. I want my daughter to be petite and my son to be the one that is a little bigger only because I never want anyone to ever get picked on. Its funny because we never think about the size of our children until we have to buy them clothing. I know that all children go through stages and eventually my son will have growth spurt and my daughter will slow down but it is funny to me that they are wearing the same size clothing this summer. I will not mention it to them (my son would be devastated) but I guess she can borrow his shorts as needed.