Just my opinion. I've played rough with my 1.5 yr old since I got her. We like to wrestle and throw each other around. I love it and so does she. She also knows when I say stop that means stop. Never has she ever been aggressive or anything like that. And she will only play rough with me. She is very gentle with others especially kids and babies. So I think as long as she does know that she only plays like this when you initiate it and stops when you say. I see no harm in it and don't think that this would lead to any aggression.