Does the bio-daddy have legal rights at all? If not, do you want him in his son's life right now?
thats difficult, if the boys father vanished for good then you can tell him when hes older, i really wouldnt know what to say because hes goin really confuse your son now, hes gotta take it slow by bonding with him slowly not rushing in
I would talk to a counselor or pastor about this. There has to be a better way than just bluntly putting it out there. Keep in mind that Dr. Laura calls the kind of dad who is only involved for a while and then disappears a "sperm donor." The man who raised your son and who he calls Daddy is his father.