The name is a personal freedom and you should be able to choose it at will. However, if someone asks you what your child's name is, it is easy to cause misunderstanding if the answer is not the surname of your parents.
It is not impossible to form a double surname, but some surnames are more troublesome. The father’s surname is Guo and the wife’s surname is Gai. Could it be that the child’s surname is Guogai? Parents' wishful thinking will cause a lot of trouble for their children in the future.