We cannot generalize based on one or two cases that we happen to know. Yes i'm sure some of you know someone who has 11 children and spends the benefits on fags. And some of you worked in benefit offices and seen some bad cases. I believe you.
I, on the other hand, spend 20 years working as a nanny for the richest and for some famous couples. The majority of them were fab parents, few of them less fab, and one of them was very sad case. Both very successful and well off. They did what some posters here suggest, they waited for the 'right time'. By that time the woman was not fertile and had to undergo fertility treatment, one after the other. In the end they went for egg donation and produced twins. By that time the poor woman was a wreck and felt that it was 'unfair' the babies didnt have her eyes. She went on to have another one. The new baby had blue eyes but was a girl and they wanted a boy. They didnt want to hold her at all . But hey, they all had their own bedrooms with expensive cots!
It is a very sad case but it is ONe case. We wouldn't say that all rich and famous people shouldn't have children or people shouldn't have IVF or twins. Because the rest of them, the majority are fab parents. The same applies to low-income parents.
Personally i am happy for my tax to support them. And if few pence of that goes to ONE bad case you know, then it is ok i can live with this. But don't use these few cases to justify that only people with over £100,000 and six bed house should have children.
FWIW i have a large house (private one) and my three children prefer to sleep in one bedroom. It is lovely watching them together.