This is really it, isn’t it? The right to procreate is not conditional, since, among other things, the right to bodily autonomy is not conditional. The answer to the problem that children are expensive and some grow up in poverty should not be, don’t let poor people have children. It shouldn’t be to discourage poor people from having children. The answer is that we must necessarily consider our society broken and failing until the time that everyone who wants children can have them without the fear of poverty. It costs money to have children? Then make sure every citizen has that money. Until that point, we do not live in a just, equitable society that provides full human rights to all its citizens.
So, fine, argue that only those who can afford it should have children. But know that you are endorsing a necessarily and fundamentally unjust society. You’re okay with depriving your fellow citizens of their basic rights. Is that really the person you want to be?