answered question 1/9/2010 Can I Put A Different Last Name On My Babys Birth Certificate When Shes Born Even If The Last Name Is Not The Biological Father's? Im Not Married, But Engaged And Want My Fiances Last Name On The BC. In SC Is It Legal? Well has a father I would say if I'm paying for my child I would want him to have my name in the end it may come back and haunt you