I'm pretty certain I'm not going to have kids.
I've been questioning myself a lot over the past few years, trying to make sure that whatever decision I make on this is one that I've thought through as much as I can, rather than being socially driven or purely biological (although no sign of any biological drive kicking in, so... who knows about that).
It's especially hard since DP already has a child, and is completely fine with whichever way I decide, so I don't even have his preference to blame 
I'm about 85% sure I don't want to have children, but every now and again I get this wave of fear that I'm making a choice I'll regret.
And the thing that feels like it reconfirms my decision not to become a mother in those moments is looking at the news.
The planet warming up, the climate migrants I already see landing on the shores of the island I live on, the narcissism of social media... Rightly or wrongly, I do feel like I'm living in an episode of Black Mirror, and I don't want to bring someone into that world.
It's definitely not the main driver of how I feel about becoming a mother, but it definitely has a role to play.
And when I look at my friends who are having children or are pregnant right now, what I feel for them is a combination of fear, hope, admiration and relief that it's not me. I love them, so I will love their kids, AND I'm genuinely scared for what they may have to live through, AND I hope that nothing but good things happen for them, AND I'm glad it's not me. I'm concerned enough about my DSS and he's a teenager and he's not even mine.
I feel so many things about it all, especially at the moment. So I kind of get where the OP is coming from (I've skimmed the thread, not RTFT), and I don't feel quite the same (although in my less thoughtful moments it might cross my mind in similar wording)