skippy

My year old neutered male collie cross dog tends to greet everyone with a growl. He seems to particularly disslike children which worries me. He has never bitten anyone and usually makes friends with adults farely quickly. Its children I worry about especially the hyper-younger ones thay I think he feels intimidated by. Any advice would be much apreciated because I am unsure how to deal with this. By the way he is a pleasant happy loving dog when he has met you.
Skippy