I agree that the focus should remain on what's best for the child, but doesn't a man have a right to legal redress when he has been defrauded in the most agreegious manor imaginable?
Georgia has sort of struck a middle ground here. Each case is decided on its own facts. If the father had no reason to suspect that the child was not his own, and he promptly takes action to disentangle himself as soon as he learns that the child may not be his own, he may do so. On the other hand, if the father does NOT take action as soon as he learns of a potential paternity question, but just lets things slide along (so that the child grows up believing that the man is his daddy) then he may NOT back out of the deal.
For some reason (the price of DNA testing went down?) we have had a fairly large number of these cases in the past 2-3 years, and the results are all over the map, depending on whether the putative father should have been suspicious or whether he took prompt action. Most extreme case was a dad who tried to get out of paying child support when the kid was THIRTEEN! (court concluded he should have known something was up when he married the woman on the rebound from another relationship and she turned up pregnant within days of the marriage. He had a blood test (not DNA test although available) done and claimed he was told that his blood type "proved" the child was his. Trial judge didn't believe this cock-and-bull story, neither did Court of Appeals.)