He's in for a tongue lashing trying to do this in court...What will he tell the judge his reasons are? That the child has Disorders? Courts don't look kindly on ANY parent who wants to 'dump' a kid once it gets too 'difficult' for them.angeleyzad said:Thanks for that info, that is basically what I have found regarding estoppel of paternity. For all that I have found, there is nothing that he can use as far as case law or statutes goes, everything says that wehre he has done this for the past 12 years, he cannot all of a sudden stop now. Wether you call it defacto parent, or whatever. I used the term legal father, because that is what is listed in their court order. The court conciders him the legal father, even though there was no formal adoption, AOP, or anything. They did have my nephew's last name changed from my sister's maiden name to his last name, about 4 or so years ago. I don't know if that would help my sister, either. The whole arguement for my nephew was "my mom, my brother, and my father, all have the same last name...I want that last name, too." So they had gone in front of the judge, and legally changed his last name.