If one assumes that this kind of altruism is hereditery. I could just as easily be cultural. I'm not so sure about extinction, but a steady state population (

If one assumes that this kind of altruism is hereditery. I could just as easily be cultural. I'm not so sure about extinction, but a steady state population (possibly with less people than now) seems pretty attractive to me. At the moment I don't believe we are culturally able to sustain this. I often wonder what needs to be done to make it happen. Probably a more equitable distribution of wealth and resources is job number one (observing that rich societies have a low fertility rate). Which probably means that it will still be many generations before it can happen.