I believe as a born-again Christian that once you've had a chance to drink from the well, it becomes your responsibility to replenish the well.
But look, I was born in 1956, the peak year for births in US history. I think I'm very representative of many of the thought processes my generation have been through and, by and large, people of my age have had their imprint planted on the consciousness of western society for a long time.
But there will come a time and a place to give back, and each individual will recognize that time and place.