Bohm,
A theist might say, "Rape is wrong because it is contrary to the character of God," or "Rape is wrong because it is contrary to God's will." This, of course, is an appeal that claims there is a God who is the ultimate judge of what is right and wrong.
But if you say, "Rape is a bad strategy because it reduces both the overall fitness of society and your chance of reproducing," how do you answer the man who says, "I don't give a damn about the overall fitness of society or my chances of reproducing. I find it to be a good strategy for maximizing my pleasure; I enjoy raping people. If that offends your sense of morality, that's your problem, not mine."