14 year old DS has been asking to for a couple years now. I changed my surname around 6 years ago. DS has my original surname, which was my father's, who I barely knew so he never met him. He says he doesn't feel any connection to the same and doesn't like having a different surname to me, he also gets teased for it at school so I understand his reasons behind wanting to do it. I know you need both parent's permission to do this but doesn't this still count if the father's name is not on his birth certificate?