what are we supposed to say again when christians ask us where we get our morality?

[Dystopia]

Where our morals come from can differ significantly. Personally mine come mainly from my parents' teaching and my own views of society as a whole, I am able to make my own mind and think critically on every problem, putting pro and con arguments and making my final decision (that can be changed if latter a better argument is presented). Personally I think the majority of morals tends to be subjective, however I also believe a small circle (eg not killing, killing is wrong etc) to be objective simply because all society regardless of religion has embraced such morals (only a minority of mentally ill people will support murder as a recreational activity)