Lord Bracknell
On fire
Experience throughout the world demonstrates that people who are in 'real' poverty need children to support them, especially in old age, because no-one else will.Is a life without children ever going to be an improved life? For many people this will not be the case, no matter how little they have.
Where there is the sort of poverty that we're talking about, not having children would obviously lead to a little more to go around for the people affected. Yes, over-population is an enormous problem, and birth control education needs to improve enormously. It would be great if families were of a 'sensible' size.
However, there is not enough desire to spread the wealth and reduce poverty - the prospects of these people will only be improved if governments in these places (and worldwide) put in the support and policies needed to do this. Otherwise, hypothetically as you say, not having children will mean that those in poverty will simply die off. Some might consider this a solution to the problem, others might consider it a little unethical.