Can there ever be universal moral truths? If not, what is the source of moral values?

This question is an example question from the ethics paper in the Philosophy IB course. If you're school has chosen for you to study the ethics paper, you will need to be familiar with the tension between cognitive realism and anti-realism. The question drills into the heart of this debate. Can we really say that there are universal moral truths? Who might support this view? Are there any problems with supporting such a position? If so, where do  we turn to next? What is the basis of our moral decisions? These questions are all really important to answer if we are to live ethical lives. Therefore this ethics question is really one worth answering and getting our heads around! Have a think!