Ask HN: Would UBI result in catastrophic population decline?
Why have children if you can live on UBI and not have to work?
Scientific consensus (I have no citation) is that human population will start to decline in a generation or two, though I don't think anyone has factored in UBI.
Do you think poverty is caused by parents who don't want to work?
Maybe, the day after UBI is implemented, everyone quits their jobs and buys a hammock and no one procreates anymore, but I don't think we're at risk of finding out.
So you wouldn't have enough money to raise children.
If children also get UBI, then you would have enough money to raise children, but the family as a whole would be poor.
Children might not like growing up in a poor family because their parents refuse to work.
UBI should lift everyone about the poverty level so no one would "grow up poor", except as a relative measurement. You can still get a job so your standard of living is higher. No one is forced to stay poor.
Children might not like growing up with parents who refuse to work, but I suspect that they will appreciate the financial security. It's the fundamental promise of a society.
That's just one possible policy. Obviously if you want people to not have children you'd choose that policy. If you want people to have children you'd choose a different policy, like paying UBI to children.
Why have children if you have to work?
I've read some dumbass reasons to oppose UBI, but this is a new frontier. It's like you got your "nobody wants to work anymore" and "there aren't enough white babies" moral panics tangled up.