My question involves name change laws in the State of: PA
I was not married to my son's father, I broke up with him when I was 4 months pregnant. He was not involved in the pregnancy. In fact we didn't even speak. He was not there at the birth, signed the AOP and then rescinded it, forced a paternity test because he didn't want to pay child support and went months without seeing our son. He now sees our son 32 hours a month, does not ask about him at any other times, doesn't go to doctors appointments, has never seen him on a holiday, etc.
Our son is now 18 months and he wants his last name changed. He would like it changed to just his last name but if that can't happen he would accept a hyphenated last name.
I am the one who does everything for my son. He lives with me. I take him to the doctor. He is on my insurance. He will go to pre school, elementary, middle and high school where we live. I will be the one responsible for registering him, getting him there, doing homework. I will be the one responsible for his extra curricular activities. If our son want to change it when he is 18 then that is his decision.
How likely would it be for a judge to order our son's last name to be changed? What would he have to get it to happen? What can I do to keep it the way it is?

