I don't believe there is a legal solution to the problems of over-population, but I am a strong believer in people paying more tax if they have children. Perhaps an extra 5% for every child they have? I really don't see why tax from my hard earned wages should go towards someone elses child benefits and their childs education.
I'm sure many will disagree with this, but children are a choice - a choice I have no wish in taking, and if you can't afford to have children, don't have them.
A perfectly reasonable view, as I have repeatedly outlined throughout this thread.
As for the legalities, this is indeed a complex problem. I fear that the tax disincentive is flawed by the fact that it is increasingly those who do not work and thus pay tax who seem to want to procreate at leisure and with no thought of the consequences beyond the immediate. And any reduction in social benefits received will most likely harm the child (who's fault it is not) and quite possibly end up promoting the offspring taking up a life of crime or antisocial behaviour, contributing nothing but negativity, to the world around him/her, since that (irresposibility) is exactly what (s)he will have learnt from the parent(s).