What is the name of your state (only U.S. law)? New York I am a single mother by choice, I never knew my twin (boy&girl) babies father, they were conceived via sperm donor. I am not married or in relationship. I would not hesitate to use my last name, but I never had a good relationship with my abusive father or his side of family. By now he is no longer in my life. I am close with my mother's side of the family, especially with my grandmother who just passed away. I love my grandmother's last name, i.e. my mother's maiden name and would like both babies have it as their last name. Is that legal in NY state? Or should I first change my last name to that name by filing a court order? That would be a huge hassle though, involving change of driver's license, Social Security card, passport, HR at work, etc. The babies are due soon, please help to find an answer so I could go on selecting them appropriate first names. Thank you.