Ideal world:
a) everyone undergoes some form of reversible sterilisation at birth
b) only reversed when you can prove yourself financially, mentally, physically and every other ally capable of bringing up children
c) after 2 children, you are sterilised permanently
That way enough money for all - decent pensions, free childcare, better standard of living, no children in poverty, university education paid for, better pay for nurses, decent council houses etc etc
I know some people would like 3 or more kids, but let's also think of the finite resources of our planet. It would also stop irresponsible people having kids with everyone they shag. Admittedly, if you had 2 kids and then formed another relationship, if you've had your quota, you won't be able to have more kids with the new partner. But them's the brakes!