What is the procedure for adoption of step child in state of georgia

The critical question is whether your son's father will oppose the adoption. It would be BEST if he would agree. That way, your son cannot argue later that you "cut off" his father "unfairly." (You know how quickly teenagers decide that something has been "unfair.")

But if the father won't agree, he can still be terminated if he has not kept substantially current on child support and/or failed substantially to communicate with him.

I handle stepfather adoptions frequently. It's usually not complicated, but dealings with the child's father CAN complicate things.