correction they wanted to have kids and only had about thirty five year windows in which to do it during a eighty year lifespan.
Double the lifespan and fertility time window and people will procrastinate. What a lot of people fail to realise is that given the choice most people don't want to be teen parents, or be a parent in their early to mid twenties. By the time they are considering it they are headed into their thirties. They usually are doing it with the knowledge at the back of their mind that if they don't do it in the next twelve to fifteen years they will lose the opportunity.
The deciding factor is the course of a womans life. twenties to thirties is prime career time, is that something she really wants to put on hold? Is she becoming a mother because she wants something to cherish and help grow or cultural and societal pressures tell her that is her purpose? Does she grow up with the thought that being female means you someday become a mommy?
Studies show that if you give women the choice of reproductive freedom children are born later and less often as young women are given a chance to build their own self identity and chose where children come into play if at all. The young women being able to choose professional reputation and career paths and secure their own futures for themselves put them and their relationships in a better position to decide when to persue family and parenting goals.
Nobody is saying no children at all. All you need is two children to every couple during their life span to bring population growth to a halt. Two parents, two kids. Parents die at 180, kids die at 212. If you however have a population choose only one child you could halve the population in a generation. Then there are those that don't want to be parents,either they are content to be aunts and uncles or teachers and then have peace at home or they don't care for children in the least or would rather persue things more personal to their life goals.
So imagine 5% no kids. 20% only one kid. and 70% two children. Leaving just 5% with three to five children. Wost case is this comes out breaking even with death rates. Best case is a drop off of population back toward the 5 billion range. Those percentages are not so hard to imagine, especially when we remove the pendulum that ticks away our chances to choose to be parents later if we want.
when you could live to 180 and be a parent as late as 165, but decide you'd like to see grand kids so choose to be a parent at 90 for the first time, it gives you time to build a reputation in your profession, secure a home and a healthy established relationship. When you've made those choices the idea of having children is much more secure and something you can devote time to doing right rather than "right now or never". Eighty years later your kids may find themselves in the same place and you'll see your first grandchild.
That's a drastic slow of the population growth. and on the whole if everybody chose the one or two child birth rate it would be a stop of birth rates as the older generate makes way.
And some will choose not to live long and extended lives. so 120 may be their limit if not more under 100. so death rates will remain higher than birth rates in some ways. But even if everybody went for extension the turn over for a generation from every 30 years to every 90 means that a three generation family would be spanning almost 300 years of time. Three hundred years from now if we've not got farms and factories elsewhere in the solar system we deserve to strangle in our depleted and polluted world to make way for a population that can do better.
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