The surname your child carries helps him identify with the rest of his family. Tradition dictates that a woman takes her husband's surname after marriage and any children born to the union also receive that surname, although many other arrangements exist today. You are not required to give your child a certain last name – or prohibited from it – simply because you gave birth to the child after your marriage ended.
Naming Your Child
When naming her child, a divorced woman has the same options as a married woman or a woman who was never married. If you are divorced from the child's father, you can give your child your ex-husband's last name or your own last name. If you'd like your child to carry his father's name but also want to share a surname with your child, you may consider giving the baby a hyphenated version of both your last names.
Your legal right to give your baby any name you please does not change if the child's father denies paternity. Thus, you can give your baby your ex-husband's last name regardless of whether he signed an Acknowledgment of Paternity form or whether a paternity test was performed. You can even give your child your ex-husband's last name if you know your ex-husband is not the child's father provided you do not do so in an attempt to commit fraud.
If your ex-husband disagrees with the name you choose for your child, he may have the option of taking the matter to court. Some states, such as Florida, have regulations in place for determining the “best interests of the child” with regard to contested names. In Florida, if the court does not specify a last name for a child whose parents are not married, the child receives a hyphenated version of both parents' last names.
Changing the Name
If you give your child your ex-husband's last name and he formally acknowledges paternity via a paternity test or Acknowledgment of Paternity form, changing the child's last name at a later date may prove difficult. A parent must generally obtain the other parent's consent before changing any part of a child's name. If your ex-husband refuses to give you permission to do so, and you cannot prove to a judge that the name change benefits your child, the child will share a surname with your ex-husband indefinitely.