Under your logic should identical twins self-identify as each other?

A second thought, yes if human values and goals are genetically encoded then we should identify with our twins to the extent that it matters much more if two agents share the same utility-function than if they share a causal history. But I believe that human values are largely a part of our upbringing, culture and education. I am not sure if humans exhibit stable goals but believe it would be important to find out what goals are universal and unmodifiable.