Change of surname of child after divorce

That is fundamentally tampering with mother nature.  You have your surname which is your dads name denoting that you are born of him.

If mother keeps her surname to her son, it will give wrong meaning and look vulgar. That is the asthetic societal part.

The legal part is you cannot, once there is the father, you may divorce and remarry that does not change the original father or his name. 

You can change, but it will be like your fahter fuced his own daughter and produced the grandchild and kept his name as surname.  just think about it. Very wrong thing to do.

Its so sad to see how you mention it as vulgar when a woman is single handedly handling everything and when she takes the role of a man why cant she give her name even the child would be proud about it. I think an affidavit to change the name would serve the purpose. You are not going to change fathers name its just the surname so it can be done