Civil Rights Law §63, allows an infant's name to be changed if there is no reasonable objection to the proposed name and that the change will substantially promote the best interest of the child. When deciding if a noncustodial parent's objection to the name change is reasonable a court will ask if the parent's concerns have to do with the best interest of the child or for some other reason such as punishing the other parent.
When considering what is the child's best interest courts will look to the totality of the circumstances. Courts will balance a series of factors to decide if a proposed name change is in the best interest of the child. The most important factors are:
(1) how much the child identifies or uses a particular surname;
(2) if the child, based on their age and maturity, has a preference for a surname and can explain that preference;
(3) if the child's surname differs from the surname of the custodial parent;
(4) whether the change in surname will effect the child's relationship;
(5) whether the child's surname is different from any of his or her siblings and how close he or she is with those siblings;
(6) whether the child is known in the community by a certain surname;
(7) any misconduct of a parent, such as failure to support the child; and
(8) whether the child will face any undue hardship, harassment or embarrassment by bearing the current or proposed surname.
If the proposed change is simply just to hyphenate the child's surname to include both parents' last names courts will conclude that the change promotes the child's best interests because it allows the child to identify and associate him or herself with both the custodial and noncustodial parent. It appears that New York Courts will not always rule that the change is in the best interest of the child if the change is more than mere hyphenation, but changing the child's surname to either the custodial parent's surname or something else.