I'll ignore the set for life part, as that would reserve the right to have a child to about 1% of the population which is ludicrous.
As for financially sound, who's to say these people weren't when they had kids? See my first point. The fact of the matter is this is an attack on working people and it's completely wrong, not even the mainstream media are behind it in full. Instead of setting these economic targets for recovery (which Osborne manages to miss anyway) we should be focussing on growing our economy and you do that by supporting low income families, boosting productivity and earning more in taxes. We're in real danger of going back into recession at this rate, the entire theory of austerity is flawed.