I think that it is sensible, logical, that people shouldn't deliberatly bring children into the world when they know they cannot provide for them.
I also know how powerful the drive to reproduce is. When I married, we couldn't really afford a child, although we were both working, we didn't earn much and had no savings. Didn't stop me wanting a child so badly I cried every time I saw one.
And then of course, there is the question of what IS 'affording' a child?
Diggerent people think they can manage on different amounts, so standing outside a situation and saying someone can't afford a child because they don't have the amount of money you feel you would have to have before you could have a child....well, it's daft really.
Also, you might be able to afford them at first, but anyone can have a change in circumstances. Lose their partner, lose their job, become ill.....what was once affordable, becomes a struggle.
We have access to contraception in this country, so are not in the same situation as people in abject poverty in the third world, who bring children into the world that they TRULY cannot afford. We do have real choice and control over our reproduction (accidents notwithstanding!)
I think that to repeatedly get pregnant because you feel you have a right to have many children and have the state support you for ever is downright disgusting. But I feel that this attitude, while existing, really is only in a minority of people. I think most people have children because they want them (even need them) and that they really think they'll be ok.