I have a year old pit bull male. (Hes getting fixed Thursday). Hes started to show dog aggression but not much and I can handle that however today he started showing aggression towards children. When he meets strangers that are adults and teenagers he is happy and loves them to pet him. Even on walks he loves the dogs he meets and the people. Today I was introducing him to my boyfriends new German Shepherd pup and he was fine. She would jump on me and him and he didn't once growl. He was fine and that was main thing I was worried about with him starting to get dog aggressive. But out of nowhere he started growing and barking at my boyfriends little cousin. She wasn't running or anything and he just went nuts. I never seen him so mad even with dogs he didn't like. I thought maybe she did something he didn't like so I put him up. I brought my cousins around him and he acted same way, growling and barking. But when my adult cousin came near he wagged his tail and let him pet him. I'm confused as to why he wouldn't like kids as he hasn't had negative experience around kids that I can recall.