Science tells us that the children of gay parents often do even better than those of straight parents. They are more confident, open, and well-adjusted. Gay parents do not create gay children. God creates gays.
Religion tells us that the love of parents is most important to a child's growth. Religion also tell us, "Do unto others as you would have them do unto you." Jesus is about real love for those who are different or are seen by society as being beyond social norms.
The only reason for anyone to oppose adoption is because the opposer feels a sense that God speaks only to them. God would not appreciate this kind of arrogance in his followers. Hate and arrogance is not what Jesus died for.
Gay parents can provide the love and stability. Gay parents were created by God for a reason -- perhaps to teach all of us that love is the only path. When you feel hate, you are not walking with God.