Earlier quoted context omitted.
* (sociologic) fear of climate change (will the world still be habitable in 20 years' time) or commitment to make a small positive impact on climate change by not having kids I'm not saying this is true or rational (there are actually blog posts in the rationalist community along the lines of "no, having kids does not cause climate change") but it's definitely a sentiment I've encountered.
That feels actually anti-rational, since if the people that care about the environment stop having children that means the people that are passing on their life outlook are mostly ignorant of the environment. It must be a US thing more though, as I haven't personally heard people say fear of environmental damage to keep them from having kids.
1. There is no scientific reason to believe the world is doomed. Go read some serious climatology papers and see for yourself. They're unreliable and exaggerated but even so, no doom.
2. State pensions and benefits might actually be doomed though given demographics. If the state can't take care of you in old age, you'd better hope you have kids who will.