“I had my son 4 years ago when I was unmarried in the state of California. His biological father refused to sign the birth certificate when he was born however, my son’s last name on his birth certificate is my last name hyphenated with his father’s last name as well. I have since married another man who has taken on the responsibilities of being my son’s father in the absence of his biological father. My husband would like to adopt him and change his last name, so I am wondering if I will have to notify my son’s biological father or have him sign off on anything in order to do so even though he did not sign the birth certificate. ”
Changing a name is a fairly simple process through the probate Court. There are some forms, and plenty of self-help books and articles available.
Adoption is more complicated. It involves terminating one parent’s rights in favor of someone else. More paperwork. Mybe a home visit from a caseworker. Start your reseach soon, or hire an attorney (or exceptionally competent paralegal) to help you.
For both processes, biological father (if known) would need to be served with notice of the proceedings effecting your son. This is true even though he is not on the birth certificate.