Well, no and yes... I think if you're young and still have plenty of time to have children, no you should not have the attitude that you will have babies even though you're broke because you'll be able to rely on government payments.
However, as a woman who is approaching 40 who has one DS and recently went through a clucky phase, time is of the essence and I am not rich. I know there's plenty of other late 30-something women out there who are single and want a baby, and I genuinely feel they ought to have every opportunity, whether they earn 30k or 150k.
It's a but if a hard question to answer, but generally speaking if someone desperately wants children and time is of the essence, then I think they should have that opportunity no matter their financial situation, although presumably they would have at least some income, a job to return to when need be.