I have a 1 year old boy and a 2 year old girl we are having a hard time with my little girl because she's always fighting with her brother she always bite him, hitting him or pushing him. I really don't know what to do we talk to her we tell her to stop when we see it coming but she don't listen. When we talk to her for example if I ask her for a favor or to stop doing something is not good she always reply NO and keep doing what she's doing. Please they are my first kids so I don't know what to do....