First, I will use this thread inappropriately and ask how does the ratings work:
Typical ratings 1 star bad 5 stars great
but since bulletin boards have so many 0 stars, does 1 star mean hey give this a look, and 5 means wow, I need to share this with everyone; or doees 1 star mean this thread is so bad, I will actually take time to rate it with a 1 star?
ok
now that I have selfishly taken up your time to ask a purely self motivated question.
I thought this was a particularly insightful rant Joe, very well thought out (my response below, probably not so much).
I also think having kids opens one's eyes to the whole new dynamic of how we humans achieve independent competent thought. It is amazing to watch as they progress through varying stages and degrees of self awareness.
My sister has a book titled Nurture BY Nature, which talks of the importance of raising kids with an awareness of their core natures. Fact of the matter is this is hard because from the moment they are born they are shaped by the very essence of their surroundings. To your point about Aiden offering up his beloved toy, one can ask, does he do this out of his nature, or is it that he has for several years, been in an environment that models that core behavior. (Knowing you and your wife, I would say that the latter is true, and thus he only sees the world through those eyes). As he goes into school, and sees other ways to deal with self he may very well start to tend towards behaviours which are less in line with the selfless behavior you described.
Even within a family, one child may be raised seeing his Dad having a life philosophy of "you do right for no other reason as it is the right thing to do" and another child may never have seen that.
Going further, I think that the concept of the human nature can run the whole gamut. A person can at his natural core may have any shade of inate selflessness or selfishness, the extreme examples of Ghandi/Mother Theresa are easily balanced by the extreme selfish acts we here on the news, such as a man throwing a baby off a bridge, or out a moving car. Society's role is to help seek a normalization and balance of those two extremes. (One might say that society would be best if we all were Ghandis, but truth is for government and community to work there has to be some natural self interest, or else wolves and predators would abuse the rest of the society - the one cult that drank the kool-aid is an example of that)
I think an interesting side point on this would be what I think of as illusory selflessness. Using Aiden again, let's say that he has seen that when he sacrifices a favorite, he earns smiles and praises, maybe even ice cream, but when he displays an attitude of gee I am sorry that happened, he simply gets a pat on the back, both receive positive reinforcement, but ice cream beats a pat on the back

. So he learns to set his self aside on the face of it, but it still has a root in self gratification. In adults illusory selflessness can even be used as a manipulative means of getting praise and satisfaction. (Note, I am not saying that was true of Aidan, merely continuing with him as a placeholder).