See:
http://online.wsj.com/article/SB10001424052748703730804576313083073123352.html
Article reads: Where does this new bio-morality leave the “naturalistic fallacy,” the idea that you cannot derive moral lessons from scientific facts—that “is” does not determine “ought”? This venerable shibboleth has been useful to generations of biologists ever since it was formally “proved” by the philosopher G.E. Moore in 1903. It absolves them of moral consequences from determining how the world actually works: “I’m just telling you how it is, not how it should be.” Prof. Churchland says the naturalistic fallacy is itself a fallacy, based on a logical mistake. We are going to have to get used to the idea that science will tell us things about the biological causes of our moral sense that themselves have moral implications.