Can a mother add her surname to her child's name without permission from the father?

My fiance's child's mother want to change the last name of the baby because she doesn't want his wife to have the same name as the child. What it comes down to and what I'm irritated about is that it puts him in the position of, if he wants his son to keep his last name AND keep the baby's mother happy, he can never get married. He's a reasonable person, tries to keep everything okay between them, and is an absolutely wonderful father. I know she has to have his permission to change the name, but can she add a name?

Can a mother add her surname to her child's name without permission from the father?
I do believe she would have to go in front of a judge and give a good reason for it
Reply:If the mother has full custody of the child, she can change it's name as many times as she wants. Adding a name is changing it. However, if the custody is shared, she can't do anything without the consent of both parents.
Reply:It varies by state but chances are she cannot get it changed without his consent if they have shared custody.





Changing and adding is in the same boat.
Reply:not after a year.
Reply:Adding a surname to the child's name IS changing it. As long as the parents share legal custody of the child (regardless of which parent has physical custody), the mother will require the father's consent to change the name, and vice versa.





You forgot another option: you don't have to take your fiance's last name when you marry him.





Then you and your fiance's child will not have the same last name, but your fiance and his child WILL. Also, nothing will have changed with the child, so the child's mother should be kept happy.