My baby is 17 mnths old I want to change his last name as he takes nuthing to do with him can I do this?

First its not a good idea to piggyback your question on someone else's. This can lead to confusion. You should start a new thread. So I've moved your question to its own thread.

A Birth Certificate is a legal document. To change one, you need a court order. Without the father's permission, you probably won't get one.

Go to your local Family Court and ask what the process is. It will differ with each court.