My dog shows aggression to strangers but not to me or my children. How likely is it that he can turn on us?

My friends and fellow dog lovers constantly tell me to get rid of him because he is an aggressive breed: a rott and chow mix. They say that he might turn on my children, yet he has always been gentle with them. However, he is very apprehensive with strangers and extremely protective of our home. He is only 8 months old and also gets along well with our other dog - a female lab, but does play very rough with her at times.