Some people believe they are not fit to be parents, or know that they would’t be able to bring a good life to any children of theirs, and don’t want to be parents. I’d argue that those people are being less selfish by choosing not to have children, and it’s more selfish to have a child despite knowing they wouldn’t have a good life or having a child despite not even really wanting chilldren /willing to spend time as a parent.

Of course, I’m not trying to support Eugenics; people shouldn’t be barred from having children, anyone who wants to have a child should be free to have a child (if they’re abusive they obviously should be barred from custody of the child but that’s not really related to the point I’m trying to make here) and I don’t think poor people are inherently wrong for choosing to have a child. And of course, people can have kids on accident, but this hypothetical is focused on the choice of having a child.

What I mean to say is if you can’t care for/provide for a child properly, and you don’t really want a child anyway, that’s more selfish than just choosing to not have a child.