My boyfriend has a son that is now 18 months old. His ex and him split when she was just barely pregnant, and due to the split and other confrontations, she vindictivly gave "there" son her last name. She claims to have done it because there are no other grandchildren that are boys and can carry on her last name. Well, she has a brother that could always have children, or more children and she claims to want a minivan full of children. What are my boyfriends right, as the father of this child, to changing his sons last name from her's to his? I was recently told that changing a childs last name has nothing to do with the state you live in, that it's a federal thing. And I was told that all the father has to do to change it, is go to the courthouse and have it done. My boyfriend signed the birth certificate, but obviously paid no attention to what he was signing. Is there anything he can do about this?