This entire thread has inspired me to take Logic 101 when I have time.
Bamboo brought up the idea of fairness, we all seem to have this concept of fairness, even the very young. What are your ideas on where this came from?
I have nothing much to add except a comment from personal experience. Small children do not understand fairness. They are egocentric and anything that doesn't go their way is declared to be "unfair". It is very hard to convince them otherwise, believe me!
They learn fairness because they experience the consequences of acting unfairly - their friends desert them, their parents punish them, etc. There's nothing metaphysical about it.
On another matter: discussing the morality of homosexuality seems as relevant as any other example (murder and rape have been mentioned previously). The fact is that societies do not agree on what is and is not moral, and the same society may change its prevailing morality in the space of a generation.
Incidentally, rape most certainly is or has been "moral" in some societies; same with child abuse. And what we might call murder has been called many other things in other times and places (eg. "human sacrifice", which was not considered immoral). I see no evidence of universal innate unchanging God-given morals among human societies.