There are a lot of gifts that come with obligations. The Japanese have several ways to say "thank you" which all denote degrees of resentment over the obligation felt. These relationships are important, as a community is much safer and stronger with co-operation, but is weakened by freeloaders. Real altruism might begin with parenting, although that is done to ensure survival of one's own genes.
However, the same pleasure centers that light up with the success of a child can also be turned on by a wide range of similar experiences. Raising an adopted, unrelated child might qualify, but there may be an expectation of support in old age. Raising a kitten will only yield affection, if that. However, there can also be great satisfaction in just giving away things one can't use any longer to where they will do the most good, or planting a tree one will never eat from.
However, the same pleasure centers that light up with the success of a child can also be turned on by a wide range of similar experiences. Raising an adopted, unrelated child might qualify, but there may be an expectation of support in old age. Raising a kitten will only yield affection, if that. However, there can also be great satisfaction in just giving away things one can't use any longer to where they will do the most good, or planting a tree one will never eat from.