What exactly are the chances of a father getting full custody? My fiance had a one night stand with someone four years ago. We just found out he may be the father of her child. She has already had two men tested. This girl is unstable, already has four other children by different fathers, has a criminal record, has custody of only half her kids. Just this past Dec she married a man who has done jail time for beating his prior wife and has at one point in this past year, held this woman hostage bc the state police were after him. If this child turns out to be my fiances, I don't know how we could in good conscience not fight tooth and nail to get full custody of him? Do we have a leg to stand on? I know how unfair the system can be.