You say it like it’s a bad thing. Like when you say you know of no “good” reason to have kids, implying that all (selfish) reasons are bad. Are they, though? I, for one, feel very grateful for my parents’ selfishness; I wouldn’t be here if not for that. Yes, they did fuck me up some, and maybe they weren’t good, selfless parents. Maybe they shouldn’t have had another child. Despite all that, here I stand, alive and well and happy to be drinking my hibiscus tea. Just because a decision is selfish it doesn’t mean it’s necessarily bad or evil, specially since all reasons not to have kids are also selfish, like you pointed out yourself.