I'm not sure it would be necessary. Kids in developed nations are already considered optional (vs. undeveloped countries where you put your kids to work so you

I'm not sure it would be necessary. Kids in developed nations are already considered optional (vs. undeveloped countries where you put your kids to work so you can eat) so as people get accustomed to having more time to raise kids then they may seem them as much less of a priority and birthrates would continue to decline to offset the increased lifespans. I do wonder what people would consider to be the age of maturity at which you are expected to be on your own. Would people expect to be cared for by their parents until they are 300?