I have friends who don't want kids for a variety of reasons (one of them both doesn't want to have children (although she WORKS with children and enjoys them and ENJOYS LEAVING THEM AT THE END OF THE DAY) and is not able to bear a child because it will literally kill her) and they get "encouragement" from their parents/in-laws, or questioned by co-workers, or whatever. Note that I SAY "friends" but really it's almost exclusively female friends.

I went through a phase (and for me it WAS a phase, for a lot of people as you're aware it is NOT a phase, please don't take that as dismissive language) where I did not want to have kids in large part because of mental health issues and fears of being a crap parent. I've changed over time and feel much more confident in my ability to raise and nurture a tiny protohuman, but it can be really hard to say "no, I probably won't have kids, because there's a chance I'll go all Andrea Yates on any child I have." :/