I can not imagine a man, worth anything as a father, who would change his mind about being the father upon learning such information, after he and the child had been around each other long enough to bond. In cases of a newborn, yeah, I can imagine it, no problem. But if I got such news after already being the "dad" for some years, I can't see how the news would change my feelings toward my child. Toward my wife, yeah, different subject.
But any man that would dramatically change his long-standing attitude towards his child based on new info like this probably shouldn't be the person for the role anyhow.
