I think a child should know both parents. As has been said, the courts will decide the best interests of the child if the parents can't work it out for themselves.
As a person who never knew her dad & had to search him out herself, I believe it is in the childs interest for the parents to work out a solution ~ once courts get involved it can leave deep scars for all concerned. Why would it be so bad for your son to know his dad? remember you must put your own feelings aside in this.
I divorced my husband ~ he was foul to the core as far as I was concerned and a pretty useless dad & partner. However I have never denied contact with his kids, and they are growing and making up their own minds. Give your son the same chance. You made him together, you should be working to bring him up together too.