Mentoring as an alternative to having children?

So… Has anyone considered that mentoring could possibly be an alternative to having children? In terms of overall psychological well-being? The studies do show that having children is inversely related to happiness, but many people choose to have children anyways since they get a different sort of satisfaction from having children.

But with mentors, they can get many of the benefits and few of the costs (plus, they’ll know unambiguously that they’ve helped someone—with parenting, it’s different). And the people they mentor are most likely more compatible with them than the children that they’ll most likely have (it’s selection bias for compatibility, basically)

That being said, maybe there is something psychological missing out from all this. I was never brought up in a loving or close family (asian parents), so I don’t really see any benefits to having a family (incidentally, this might be one huge reason why the fertility rate in places like Taiwan/​Japan/​South Korea are now among the lowest rates in the world—see http://​​​​wiki/​​List_of_countries_and_territories_by_fertility_rate#The_CIA_TFR_Ranking ).