I got pregnant in my last year of high school.At the time me and the father of my child were not together so thinking of letting my grandparents adopt my son I let them talk me into giving him their last name. On the birth certificate is my name and the fathers name and I decided not to have them adopt him unless I couldn't take care of him on my own. Two years later me and my sons father have worked things out and decided to get married but my grandparents are saying they can take my son away because he has their last name (they aren't happy about the marriage due to religion) can they do this? And what do I have to do to change my sons last name to his fathers? Any help please :)

Was it in writing that you gave them custody or guardianship ? Was it through the courts ?

Neither. Which is why I'm not sure if this situation is really as difficult as my family is making it seem. I'm only 20 and I don't have any experience with these types of things. :(

If you are in the united states, you could have named your child Brad Pitt and your grandparents still would have no rights. You can name a child anything you want. The only one with any rights is you and the father and your grandparents probably would not even be heard in a court.

As for changing your child's name - you and the father go to the family court (clerk most likely) and file for a name change. There will be a small fee and you may need to see the judge but it's a simple thing if both parents are present.

Your grandparents have no right to take your child away as long as you are giving it proper care. The name on the birth certificate matters not. Especially since the actual parents are listed. As Steve said, as long as both parents agree, changing the birth certificate will be a simple task.