Anecdata: I am 33 and have 0 kids. I make good money but, due to poor financial literacy at a young age, I am shackled with a hefty amount of student loan debt well into my 30s. My 20s were financially precarious and it would've been irresponsible to bring a child into the mix. Would've been nice, but it just wasn't going to happen.

I don't think that my specific situation applies to everyone, but I also don't expect I'm alone on this one.