Change Baby Last Name - Not The Dad?

Hey! So this is not about any particular person, but I know there are situations that may happen like this. I was writing a paper and doing a survey and one of my friends say one thing and I think another.

Let’s say a baby that’s a few months old has a mans last name and later the parents find out he is not the biological son, is there a law that says you have to change the child’s last name? So the father should definitely be removed but the last name is not necessary.

Our office is in NJ ask this would be could for anyone around those areas NJ , NY,CT, etcetera.

As a side note, the Article my friend is writing talks about how some people may have other kids with that person and may want to keep their name all the same for school purposes and to keep the herd identified together. Other reason may be becaue its too much work to change. Another reason may be simple that the person likes the name.

So what do you all think? Anyone ever go through it? Any ideas?

Thanks